test(pgsql, reflectutil): ✨ add comprehensive test coverage

* Introduce tests for PostgreSQL data types and keywords.
* Implement tests for reflect utility functions.
* Ensure consistency and correctness of type conversions and keyword mappings.
* Validate behavior for various edge cases and input types.

pkg/commontypes/commontypes_test.go

@@ -0,0 +1,714 @@
+package commontypes
+
+import (
+	"testing"
+)
+
+func TestExtractBaseType(t *testing.T) {
+	tests := []struct {
+		name    string
+		sqlType string
+		want    string
+	}{
+		{"varchar with length", "varchar(100)", "varchar"},
+		{"VARCHAR uppercase with length", "VARCHAR(255)", "varchar"},
+		{"numeric with precision", "numeric(10,2)", "numeric"},
+		{"NUMERIC uppercase", "NUMERIC(18,4)", "numeric"},
+		{"decimal with precision", "decimal(15,3)", "decimal"},
+		{"char with length", "char(50)", "char"},
+		{"simple integer", "integer", "integer"},
+		{"simple text", "text", "text"},
+		{"bigint", "bigint", "bigint"},
+		{"With spaces", " varchar(100) ", "varchar"},
+		{"No parentheses", "boolean", "boolean"},
+		{"Empty string", "", ""},
+		{"Mixed case", "VarChar(100)", "varchar"},
+		{"timestamp with time zone", "timestamp(6) with time zone", "timestamp"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ExtractBaseType(tt.sqlType)
+			if got != tt.want {
+				t.Errorf("ExtractBaseType(%q) = %q, want %q", tt.sqlType, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNormalizeType(t *testing.T) {
+	// NormalizeType is an alias for ExtractBaseType, test that they behave the same
+	testCases := []string{
+		"varchar(100)",
+		"numeric(10,2)",
+		"integer",
+		"text",
+		" VARCHAR(255) ",
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc, func(t *testing.T) {
+			extracted := ExtractBaseType(tc)
+			normalized := NormalizeType(tc)
+			if extracted != normalized {
+				t.Errorf("ExtractBaseType(%q) = %q, but NormalizeType(%q) = %q",
+					tc, extracted, tc, normalized)
+			}
+		})
+	}
+}
+
+func TestSQLToGo(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "int32"},
+		{"bigint nullable", "bigint", true, "int64"},
+		{"smallint nullable", "smallint", true, "int16"},
+		{"serial nullable", "serial", true, "int32"},
+
+		// Integer types (not nullable)
+		{"integer not nullable", "integer", false, "*int32"},
+		{"bigint not nullable", "bigint", false, "*int64"},
+		{"smallint not nullable", "smallint", false, "*int16"},
+
+		// String types (nullable)
+		{"text nullable", "text", true, "string"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar with length nullable", "varchar(100)", true, "string"},
+
+		// String types (not nullable)
+		{"text not nullable", "text", false, "*string"},
+		{"varchar not nullable", "varchar", false, "*string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "*bool"},
+
+		// Float types
+		{"real nullable", "real", true, "float32"},
+		{"double precision nullable", "double precision", true, "float64"},
+		{"real not nullable", "real", false, "*float32"},
+		{"double precision not nullable", "double precision", false, "*float64"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "time.Time"},
+		{"date nullable", "date", true, "time.Time"},
+		{"timestamp not nullable", "timestamp", false, "*time.Time"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "[]byte"},
+		{"bytea not nullable", "bytea", false, "[]byte"}, // Slices don't get pointer
+
+		// UUID
+		{"uuid nullable", "uuid", true, "string"},
+		{"uuid not nullable", "uuid", false, "*string"},
+
+		// JSON
+		{"json nullable", "json", true, "string"},
+		{"jsonb nullable", "jsonb", true, "string"},
+
+		// Array
+		{"array nullable", "array", true, "[]string"},
+		{"array not nullable", "array", false, "[]string"}, // Slices don't get pointer
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "interface{}"},
+		{"unknown type not nullable", "unknowntype", false, "interface{}"}, // Interface doesn't get pointer
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToGo(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToGo(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToTypeScript(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types
+		{"integer nullable", "integer", true, "number"},
+		{"integer not nullable", "integer", false, "number | null"},
+		{"bigint nullable", "bigint", true, "number"},
+		{"bigint not nullable", "bigint", false, "number | null"},
+
+		// String types
+		{"text nullable", "text", true, "string"},
+		{"text not nullable", "text", false, "string | null"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar(100) nullable", "varchar(100)", true, "string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "boolean"},
+		{"boolean not nullable", "boolean", false, "boolean | null"},
+
+		// Float types
+		{"real nullable", "real", true, "number"},
+		{"double precision nullable", "double precision", true, "number"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "Date"},
+		{"date nullable", "date", true, "Date"},
+		{"timestamp not nullable", "timestamp", false, "Date | null"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "Buffer"},
+		{"bytea not nullable", "bytea", false, "Buffer | null"},
+
+		// JSON
+		{"json nullable", "json", true, "any"},
+		{"jsonb nullable", "jsonb", true, "any"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "string"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "any"},
+		{"unknown type not nullable", "unknowntype", false, "any | null"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToTypeScript(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToTypeScript(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToPython(t *testing.T) {
+	tests := []struct {
+		name    string
+		sqlType string
+		want    string
+	}{
+		// Integer types
+		{"integer", "integer", "int"},
+		{"bigint", "bigint", "int"},
+		{"smallint", "smallint", "int"},
+
+		// String types
+		{"text", "text", "str"},
+		{"varchar", "varchar", "str"},
+		{"varchar(100)", "varchar(100)", "str"},
+
+		// Boolean
+		{"boolean", "boolean", "bool"},
+
+		// Float types
+		{"real", "real", "float"},
+		{"double precision", "double precision", "float"},
+		{"numeric", "numeric", "Decimal"},
+		{"decimal", "decimal", "Decimal"},
+
+		// Date/Time types
+		{"timestamp", "timestamp", "datetime"},
+		{"date", "date", "date"},
+		{"time", "time", "time"},
+
+		// Binary
+		{"bytea", "bytea", "bytes"},
+
+		// JSON
+		{"json", "json", "dict"},
+		{"jsonb", "jsonb", "dict"},
+
+		// UUID
+		{"uuid", "uuid", "UUID"},
+
+		// Array
+		{"array", "array", "list"},
+
+		// Unknown types
+		{"unknown type", "unknowntype", "Any"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToPython(tt.sqlType)
+			if got != tt.want {
+				t.Errorf("SQLToPython(%q) = %q, want %q", tt.sqlType, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToCSharp(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "int"},
+		{"bigint nullable", "bigint", true, "long"},
+		{"smallint nullable", "smallint", true, "short"},
+
+		// Integer types (not nullable - value types get ?)
+		{"integer not nullable", "integer", false, "int?"},
+		{"bigint not nullable", "bigint", false, "long?"},
+		{"smallint not nullable", "smallint", false, "short?"},
+
+		// String types (reference types, no ? needed)
+		{"text nullable", "text", true, "string"},
+		{"text not nullable", "text", false, "string"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar(100) nullable", "varchar(100)", true, "string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "bool?"},
+
+		// Float types
+		{"real nullable", "real", true, "float"},
+		{"double precision nullable", "double precision", true, "double"},
+		{"decimal nullable", "decimal", true, "decimal"},
+		{"real not nullable", "real", false, "float?"},
+		{"double precision not nullable", "double precision", false, "double?"},
+		{"decimal not nullable", "decimal", false, "decimal?"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "DateTime"},
+		{"date nullable", "date", true, "DateTime"},
+		{"timestamptz nullable", "timestamptz", true, "DateTimeOffset"},
+		{"timestamp not nullable", "timestamp", false, "DateTime?"},
+		{"timestamptz not nullable", "timestamptz", false, "DateTimeOffset?"},
+
+		// Binary (array type, no ?)
+		{"bytea nullable", "bytea", true, "byte[]"},
+		{"bytea not nullable", "bytea", false, "byte[]"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "Guid"},
+		{"uuid not nullable", "uuid", false, "Guid?"},
+
+		// JSON
+		{"json nullable", "json", true, "string"},
+
+		// Unknown types (object is reference type)
+		{"unknown type nullable", "unknowntype", true, "object"},
+		{"unknown type not nullable", "unknowntype", false, "object"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToCSharp(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToCSharp(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNeedsTimeImport(t *testing.T) {
+	tests := []struct {
+		name   string
+		goType string
+		want   bool
+	}{
+		{"time.Time type", "time.Time", true},
+		{"pointer to time.Time", "*time.Time", true},
+		{"int32 type", "int32", false},
+		{"string type", "string", false},
+		{"bool type", "bool", false},
+		{"[]byte type", "[]byte", false},
+		{"interface{}", "interface{}", false},
+		{"empty string", "", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := NeedsTimeImport(tt.goType)
+			if got != tt.want {
+				t.Errorf("NeedsTimeImport(%q) = %v, want %v", tt.goType, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGoTypeMap(t *testing.T) {
+	// Test that the map contains expected entries
+	expectedMappings := map[string]string{
+		"integer":          "int32",
+		"bigint":           "int64",
+		"text":             "string",
+		"boolean":          "bool",
+		"double precision": "float64",
+		"bytea":            "[]byte",
+		"timestamp":        "time.Time",
+		"uuid":             "string",
+		"json":             "string",
+	}
+
+	for sqlType, expectedGoType := range expectedMappings {
+		if goType, ok := GoTypeMap[sqlType]; !ok {
+			t.Errorf("GoTypeMap missing entry for %q", sqlType)
+		} else if goType != expectedGoType {
+			t.Errorf("GoTypeMap[%q] = %q, want %q", sqlType, goType, expectedGoType)
+		}
+	}
+
+	if len(GoTypeMap) == 0 {
+		t.Error("GoTypeMap is empty")
+	}
+}
+
+func TestTypeScriptTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "number",
+		"bigint":           "number",
+		"text":             "string",
+		"boolean":          "boolean",
+		"double precision": "number",
+		"bytea":            "Buffer",
+		"timestamp":        "Date",
+		"uuid":             "string",
+		"json":             "any",
+	}
+
+	for sqlType, expectedTSType := range expectedMappings {
+		if tsType, ok := TypeScriptTypeMap[sqlType]; !ok {
+			t.Errorf("TypeScriptTypeMap missing entry for %q", sqlType)
+		} else if tsType != expectedTSType {
+			t.Errorf("TypeScriptTypeMap[%q] = %q, want %q", sqlType, tsType, expectedTSType)
+		}
+	}
+
+	if len(TypeScriptTypeMap) == 0 {
+		t.Error("TypeScriptTypeMap is empty")
+	}
+}
+
+func TestPythonTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer": "int",
+		"bigint":  "int",
+		"text":    "str",
+		"boolean": "bool",
+		"real":    "float",
+		"numeric": "Decimal",
+		"bytea":   "bytes",
+		"date":    "date",
+		"uuid":    "UUID",
+		"json":    "dict",
+	}
+
+	for sqlType, expectedPyType := range expectedMappings {
+		if pyType, ok := PythonTypeMap[sqlType]; !ok {
+			t.Errorf("PythonTypeMap missing entry for %q", sqlType)
+		} else if pyType != expectedPyType {
+			t.Errorf("PythonTypeMap[%q] = %q, want %q", sqlType, pyType, expectedPyType)
+		}
+	}
+
+	if len(PythonTypeMap) == 0 {
+		t.Error("PythonTypeMap is empty")
+	}
+}
+
+func TestCSharpTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "int",
+		"bigint":           "long",
+		"smallint":         "short",
+		"text":             "string",
+		"boolean":          "bool",
+		"double precision": "double",
+		"decimal":          "decimal",
+		"bytea":            "byte[]",
+		"timestamp":        "DateTime",
+		"uuid":             "Guid",
+		"json":             "string",
+	}
+
+	for sqlType, expectedCSType := range expectedMappings {
+		if csType, ok := CSharpTypeMap[sqlType]; !ok {
+			t.Errorf("CSharpTypeMap missing entry for %q", sqlType)
+		} else if csType != expectedCSType {
+			t.Errorf("CSharpTypeMap[%q] = %q, want %q", sqlType, csType, expectedCSType)
+		}
+	}
+
+	if len(CSharpTypeMap) == 0 {
+		t.Error("CSharpTypeMap is empty")
+	}
+}
+
+func TestSQLToJava(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types
+		{"integer nullable", "integer", true, "Integer"},
+		{"integer not nullable", "integer", false, "Integer"},
+		{"bigint nullable", "bigint", true, "Long"},
+		{"smallint nullable", "smallint", true, "Short"},
+
+		// String types
+		{"text nullable", "text", true, "String"},
+		{"varchar nullable", "varchar", true, "String"},
+		{"varchar(100) nullable", "varchar(100)", true, "String"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "Boolean"},
+
+		// Float types
+		{"real nullable", "real", true, "Float"},
+		{"double precision nullable", "double precision", true, "Double"},
+		{"numeric nullable", "numeric", true, "BigDecimal"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "Timestamp"},
+		{"date nullable", "date", true, "Date"},
+		{"time nullable", "time", true, "Time"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "byte[]"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "UUID"},
+
+		// JSON
+		{"json nullable", "json", true, "String"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "Object"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToJava(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToJava(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToPhp(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "int"},
+		{"bigint nullable", "bigint", true, "int"},
+		{"smallint nullable", "smallint", true, "int"},
+
+		// Integer types (not nullable)
+		{"integer not nullable", "integer", false, "?int"},
+		{"bigint not nullable", "bigint", false, "?int"},
+
+		// String types
+		{"text nullable", "text", true, "string"},
+		{"text not nullable", "text", false, "?string"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar(100) nullable", "varchar(100)", true, "string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "?bool"},
+
+		// Float types
+		{"real nullable", "real", true, "float"},
+		{"double precision nullable", "double precision", true, "float"},
+		{"real not nullable", "real", false, "?float"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "\\DateTime"},
+		{"date nullable", "date", true, "\\DateTime"},
+		{"timestamp not nullable", "timestamp", false, "?\\DateTime"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "string"},
+		{"bytea not nullable", "bytea", false, "?string"},
+
+		// JSON
+		{"json nullable", "json", true, "array"},
+		{"json not nullable", "json", false, "?array"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "string"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "mixed"},
+		{"unknown type not nullable", "unknowntype", false, "mixed"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToPhp(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToPhp(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToRust(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "i32"},
+		{"bigint nullable", "bigint", true, "i64"},
+		{"smallint nullable", "smallint", true, "i16"},
+
+		// Integer types (not nullable)
+		{"integer not nullable", "integer", false, "Option<i32>"},
+		{"bigint not nullable", "bigint", false, "Option<i64>"},
+		{"smallint not nullable", "smallint", false, "Option<i16>"},
+
+		// String types
+		{"text nullable", "text", true, "String"},
+		{"text not nullable", "text", false, "Option<String>"},
+		{"varchar nullable", "varchar", true, "String"},
+		{"varchar(100) nullable", "varchar(100)", true, "String"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "Option<bool>"},
+
+		// Float types
+		{"real nullable", "real", true, "f32"},
+		{"double precision nullable", "double precision", true, "f64"},
+		{"real not nullable", "real", false, "Option<f32>"},
+		{"double precision not nullable", "double precision", false, "Option<f64>"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "NaiveDateTime"},
+		{"timestamptz nullable", "timestamptz", true, "DateTime<Utc>"},
+		{"date nullable", "date", true, "NaiveDate"},
+		{"time nullable", "time", true, "NaiveTime"},
+		{"timestamp not nullable", "timestamp", false, "Option<NaiveDateTime>"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "Vec<u8>"},
+		{"bytea not nullable", "bytea", false, "Option<Vec<u8>>"},
+
+		// JSON
+		{"json nullable", "json", true, "serde_json::Value"},
+		{"json not nullable", "json", false, "Option<serde_json::Value>"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "String"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "String"},
+		{"unknown type not nullable", "unknowntype", false, "Option<String>"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToRust(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToRust(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestJavaTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "Integer",
+		"bigint":           "Long",
+		"smallint":         "Short",
+		"text":             "String",
+		"boolean":          "Boolean",
+		"double precision": "Double",
+		"numeric":          "BigDecimal",
+		"bytea":            "byte[]",
+		"timestamp":        "Timestamp",
+		"uuid":             "UUID",
+		"date":             "Date",
+	}
+
+	for sqlType, expectedJavaType := range expectedMappings {
+		if javaType, ok := JavaTypeMap[sqlType]; !ok {
+			t.Errorf("JavaTypeMap missing entry for %q", sqlType)
+		} else if javaType != expectedJavaType {
+			t.Errorf("JavaTypeMap[%q] = %q, want %q", sqlType, javaType, expectedJavaType)
+		}
+	}
+
+	if len(JavaTypeMap) == 0 {
+		t.Error("JavaTypeMap is empty")
+	}
+}
+
+func TestPHPTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "int",
+		"bigint":           "int",
+		"text":             "string",
+		"boolean":          "bool",
+		"double precision": "float",
+		"bytea":            "string",
+		"timestamp":        "\\DateTime",
+		"uuid":             "string",
+		"json":             "array",
+	}
+
+	for sqlType, expectedPHPType := range expectedMappings {
+		if phpType, ok := PHPTypeMap[sqlType]; !ok {
+			t.Errorf("PHPTypeMap missing entry for %q", sqlType)
+		} else if phpType != expectedPHPType {
+			t.Errorf("PHPTypeMap[%q] = %q, want %q", sqlType, phpType, expectedPHPType)
+		}
+	}
+
+	if len(PHPTypeMap) == 0 {
+		t.Error("PHPTypeMap is empty")
+	}
+}
+
+func TestRustTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "i32",
+		"bigint":           "i64",
+		"smallint":         "i16",
+		"text":             "String",
+		"boolean":          "bool",
+		"double precision": "f64",
+		"real":             "f32",
+		"bytea":            "Vec<u8>",
+		"timestamp":        "NaiveDateTime",
+		"timestamptz":      "DateTime<Utc>",
+		"date":             "NaiveDate",
+		"json":             "serde_json::Value",
+	}
+
+	for sqlType, expectedRustType := range expectedMappings {
+		if rustType, ok := RustTypeMap[sqlType]; !ok {
+			t.Errorf("RustTypeMap missing entry for %q", sqlType)
+		} else if rustType != expectedRustType {
+			t.Errorf("RustTypeMap[%q] = %q, want %q", sqlType, rustType, expectedRustType)
+		}
+	}
+
+	if len(RustTypeMap) == 0 {
+		t.Error("RustTypeMap is empty")
+	}
+}

pkg/diff/diff_test.go

@@ -0,0 +1,558 @@
+package diff
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestCompareDatabases(t *testing.T) {
+	tests := []struct {
+		name   string
+		source *models.Database
+		target *models.Database
+		want   func(*DiffResult) bool
+	}{
+		{
+			name: "identical databases",
+			source: &models.Database{
+				Name:    "source",
+				Schemas: []*models.Schema{},
+			},
+			target: &models.Database{
+				Name:    "target",
+				Schemas: []*models.Schema{},
+			},
+			want: func(r *DiffResult) bool {
+				return r.Source == "source" && r.Target == "target" &&
+					len(r.Schemas.Missing) == 0 && len(r.Schemas.Extra) == 0
+			},
+		},
+		{
+			name: "different schemas",
+			source: &models.Database{
+				Name: "source",
+				Schemas: []*models.Schema{
+					{Name: "public"},
+				},
+			},
+			target: &models.Database{
+				Name:    "target",
+				Schemas: []*models.Schema{},
+			},
+			want: func(r *DiffResult) bool {
+				return len(r.Schemas.Missing) == 1 && r.Schemas.Missing[0].Name == "public"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := CompareDatabases(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("CompareDatabases() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareColumns(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Column
+		target map[string]*models.Column
+		want   func(*ColumnDiff) bool
+	}{
+		{
+			name:   "identical columns",
+			source: map[string]*models.Column{},
+			target: map[string]*models.Column{},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing column",
+			source: map[string]*models.Column{
+				"id": {Name: "id", Type: "integer"},
+			},
+			target: map[string]*models.Column{},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "id"
+			},
+		},
+		{
+			name:   "extra column",
+			source: map[string]*models.Column{},
+			target: map[string]*models.Column{
+				"id": {Name: "id", Type: "integer"},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "id"
+			},
+		},
+		{
+			name: "modified column type",
+			source: map[string]*models.Column{
+				"id": {Name: "id", Type: "integer"},
+			},
+			target: map[string]*models.Column{
+				"id": {Name: "id", Type: "bigint"},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Name == "id" &&
+					d.Modified[0].Changes["type"] != nil
+			},
+		},
+		{
+			name: "modified column nullable",
+			source: map[string]*models.Column{
+				"name": {Name: "name", Type: "text", NotNull: true},
+			},
+			target: map[string]*models.Column{
+				"name": {Name: "name", Type: "text", NotNull: false},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Changes["not_null"] != nil
+			},
+		},
+		{
+			name: "modified column length",
+			source: map[string]*models.Column{
+				"name": {Name: "name", Type: "varchar", Length: 100},
+			},
+			target: map[string]*models.Column{
+				"name": {Name: "name", Type: "varchar", Length: 255},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Changes["length"] != nil
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareColumns(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareColumns() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareColumnDetails(t *testing.T) {
+	tests := []struct {
+		name   string
+		source *models.Column
+		target *models.Column
+		want   int // number of changes
+	}{
+		{
+			name:   "identical columns",
+			source: &models.Column{Name: "id", Type: "integer"},
+			target: &models.Column{Name: "id", Type: "integer"},
+			want:   0,
+		},
+		{
+			name:   "type change",
+			source: &models.Column{Name: "id", Type: "integer"},
+			target: &models.Column{Name: "id", Type: "bigint"},
+			want:   1,
+		},
+		{
+			name:   "length change",
+			source: &models.Column{Name: "name", Type: "varchar", Length: 100},
+			target: &models.Column{Name: "name", Type: "varchar", Length: 255},
+			want:   1,
+		},
+		{
+			name:   "precision change",
+			source: &models.Column{Name: "price", Type: "numeric", Precision: 10},
+			target: &models.Column{Name: "price", Type: "numeric", Precision: 12},
+			want:   1,
+		},
+		{
+			name:   "scale change",
+			source: &models.Column{Name: "price", Type: "numeric", Scale: 2},
+			target: &models.Column{Name: "price", Type: "numeric", Scale: 4},
+			want:   1,
+		},
+		{
+			name:   "not null change",
+			source: &models.Column{Name: "name", Type: "text", NotNull: true},
+			target: &models.Column{Name: "name", Type: "text", NotNull: false},
+			want:   1,
+		},
+		{
+			name:   "auto increment change",
+			source: &models.Column{Name: "id", Type: "integer", AutoIncrement: true},
+			target: &models.Column{Name: "id", Type: "integer", AutoIncrement: false},
+			want:   1,
+		},
+		{
+			name:   "primary key change",
+			source: &models.Column{Name: "id", Type: "integer", IsPrimaryKey: true},
+			target: &models.Column{Name: "id", Type: "integer", IsPrimaryKey: false},
+			want:   1,
+		},
+		{
+			name:   "multiple changes",
+			source: &models.Column{Name: "id", Type: "integer", NotNull: true, AutoIncrement: true},
+			target: &models.Column{Name: "id", Type: "bigint", NotNull: false, AutoIncrement: false},
+			want:   3,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareColumnDetails(tt.source, tt.target)
+			if len(got) != tt.want {
+				t.Errorf("compareColumnDetails() = %d changes, want %d", len(got), tt.want)
+			}
+		})
+	}
+}
+
+func TestCompareIndexes(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Index
+		target map[string]*models.Index
+		want   func(*IndexDiff) bool
+	}{
+		{
+			name:   "identical indexes",
+			source: map[string]*models.Index{},
+			target: map[string]*models.Index{},
+			want: func(d *IndexDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing index",
+			source: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}},
+			},
+			target: map[string]*models.Index{},
+			want: func(d *IndexDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "idx_name"
+			},
+		},
+		{
+			name:   "extra index",
+			source: map[string]*models.Index{},
+			target: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}},
+			},
+			want: func(d *IndexDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "idx_name"
+			},
+		},
+		{
+			name: "modified index uniqueness",
+			source: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}, Unique: false},
+			},
+			target: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}, Unique: true},
+			},
+			want: func(d *IndexDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Name == "idx_name"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareIndexes(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareIndexes() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareConstraints(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Constraint
+		target map[string]*models.Constraint
+		want   func(*ConstraintDiff) bool
+	}{
+		{
+			name:   "identical constraints",
+			source: map[string]*models.Constraint{},
+			target: map[string]*models.Constraint{},
+			want: func(d *ConstraintDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing constraint",
+			source: map[string]*models.Constraint{
+				"pk_id": {Name: "pk_id", Type: "PRIMARY KEY", Columns: []string{"id"}},
+			},
+			target: map[string]*models.Constraint{},
+			want: func(d *ConstraintDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "pk_id"
+			},
+		},
+		{
+			name:   "extra constraint",
+			source: map[string]*models.Constraint{},
+			target: map[string]*models.Constraint{
+				"pk_id": {Name: "pk_id", Type: "PRIMARY KEY", Columns: []string{"id"}},
+			},
+			want: func(d *ConstraintDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "pk_id"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareConstraints(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareConstraints() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareRelationships(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Relationship
+		target map[string]*models.Relationship
+		want   func(*RelationshipDiff) bool
+	}{
+		{
+			name:   "identical relationships",
+			source: map[string]*models.Relationship{},
+			target: map[string]*models.Relationship{},
+			want: func(d *RelationshipDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing relationship",
+			source: map[string]*models.Relationship{
+				"fk_user": {Name: "fk_user", Type: "FOREIGN KEY"},
+			},
+			target: map[string]*models.Relationship{},
+			want: func(d *RelationshipDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "fk_user"
+			},
+		},
+		{
+			name:   "extra relationship",
+			source: map[string]*models.Relationship{},
+			target: map[string]*models.Relationship{
+				"fk_user": {Name: "fk_user", Type: "FOREIGN KEY"},
+			},
+			want: func(d *RelationshipDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "fk_user"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareRelationships(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareRelationships() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareTables(t *testing.T) {
+	tests := []struct {
+		name   string
+		source []*models.Table
+		target []*models.Table
+		want   func(*TableDiff) bool
+	}{
+		{
+			name:   "identical tables",
+			source: []*models.Table{},
+			target: []*models.Table{},
+			want: func(d *TableDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing table",
+			source: []*models.Table{
+				{Name: "users", Schema: "public"},
+			},
+			target: []*models.Table{},
+			want: func(d *TableDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "users"
+			},
+		},
+		{
+			name:   "extra table",
+			source: []*models.Table{},
+			target: []*models.Table{
+				{Name: "users", Schema: "public"},
+			},
+			want: func(d *TableDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "users"
+			},
+		},
+		{
+			name: "modified table",
+			source: []*models.Table{
+				{
+					Name:   "users",
+					Schema: "public",
+					Columns: map[string]*models.Column{
+						"id": {Name: "id", Type: "integer"},
+					},
+				},
+			},
+			target: []*models.Table{
+				{
+					Name:   "users",
+					Schema: "public",
+					Columns: map[string]*models.Column{
+						"id": {Name: "id", Type: "bigint"},
+					},
+				},
+			},
+			want: func(d *TableDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Name == "users"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareTables(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareTables() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareSchemas(t *testing.T) {
+	tests := []struct {
+		name   string
+		source []*models.Schema
+		target []*models.Schema
+		want   func(*SchemaDiff) bool
+	}{
+		{
+			name:   "identical schemas",
+			source: []*models.Schema{},
+			target: []*models.Schema{},
+			want: func(d *SchemaDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing schema",
+			source: []*models.Schema{
+				{Name: "public"},
+			},
+			target: []*models.Schema{},
+			want: func(d *SchemaDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "public"
+			},
+		},
+		{
+			name:   "extra schema",
+			source: []*models.Schema{},
+			target: []*models.Schema{
+				{Name: "public"},
+			},
+			want: func(d *SchemaDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "public"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareSchemas(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareSchemas() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestIsEmpty(t *testing.T) {
+	tests := []struct {
+		name string
+		v    interface{}
+		want bool
+	}{
+		{"empty ColumnDiff", &ColumnDiff{Missing: []*models.Column{}, Extra: []*models.Column{}, Modified: []*ColumnChange{}}, true},
+		{"ColumnDiff with missing", &ColumnDiff{Missing: []*models.Column{{Name: "id"}}, Extra: []*models.Column{}, Modified: []*ColumnChange{}}, false},
+		{"ColumnDiff with extra", &ColumnDiff{Missing: []*models.Column{}, Extra: []*models.Column{{Name: "id"}}, Modified: []*ColumnChange{}}, false},
+		{"empty IndexDiff", &IndexDiff{Missing: []*models.Index{}, Extra: []*models.Index{}, Modified: []*IndexChange{}}, true},
+		{"IndexDiff with missing", &IndexDiff{Missing: []*models.Index{{Name: "idx"}}, Extra: []*models.Index{}, Modified: []*IndexChange{}}, false},
+		{"empty TableDiff", &TableDiff{Missing: []*models.Table{}, Extra: []*models.Table{}, Modified: []*TableChange{}}, true},
+		{"TableDiff with extra", &TableDiff{Missing: []*models.Table{}, Extra: []*models.Table{{Name: "users"}}, Modified: []*TableChange{}}, false},
+		{"empty ConstraintDiff", &ConstraintDiff{Missing: []*models.Constraint{}, Extra: []*models.Constraint{}, Modified: []*ConstraintChange{}}, true},
+		{"empty RelationshipDiff", &RelationshipDiff{Missing: []*models.Relationship{}, Extra: []*models.Relationship{}, Modified: []*RelationshipChange{}}, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := isEmpty(tt.v)
+			if got != tt.want {
+				t.Errorf("isEmpty() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestComputeSummary(t *testing.T) {
+	tests := []struct {
+		name   string
+		result *DiffResult
+		want   func(*Summary) bool
+	}{
+		{
+			name: "empty diff",
+			result: &DiffResult{
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{},
+					Extra:    []*models.Schema{},
+					Modified: []*SchemaChange{},
+				},
+			},
+			want: func(s *Summary) bool {
+				return s.Schemas.Missing == 0 && s.Schemas.Extra == 0 && s.Schemas.Modified == 0
+			},
+		},
+		{
+			name: "schemas with differences",
+			result: &DiffResult{
+				Schemas: &SchemaDiff{
+					Missing: []*models.Schema{{Name: "schema1"}},
+					Extra:   []*models.Schema{{Name: "schema2"}, {Name: "schema3"}},
+					Modified: []*SchemaChange{
+						{Name: "public"},
+					},
+				},
+			},
+			want: func(s *Summary) bool {
+				return s.Schemas.Missing == 1 && s.Schemas.Extra == 2 && s.Schemas.Modified == 1
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ComputeSummary(tt.result)
+			if !tt.want(got) {
+				t.Errorf("ComputeSummary() result doesn't match expectations")
+			}
+		})
+	}
+}

pkg/diff/formatters_test.go

@@ -0,0 +1,440 @@
+package diff
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestFormatDiff(t *testing.T) {
+	result := &DiffResult{
+		Source: "source_db",
+		Target: "target_db",
+		Schemas: &SchemaDiff{
+			Missing:  []*models.Schema{},
+			Extra:    []*models.Schema{},
+			Modified: []*SchemaChange{},
+		},
+	}
+
+	tests := []struct {
+		name    string
+		format  OutputFormat
+		wantErr bool
+	}{
+		{"summary format", FormatSummary, false},
+		{"json format", FormatJSON, false},
+		{"html format", FormatHTML, false},
+		{"invalid format", OutputFormat("invalid"), true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			err := FormatDiff(result, tt.format, &buf)
+
+			if (err != nil) != tt.wantErr {
+				t.Errorf("FormatDiff() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			if !tt.wantErr && buf.Len() == 0 {
+				t.Error("FormatDiff() produced empty output")
+			}
+		})
+	}
+}
+
+func TestFormatSummary(t *testing.T) {
+	tests := []struct {
+		name    string
+		result  *DiffResult
+		wantStr []string // strings that should appear in output
+	}{
+		{
+			name: "no differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{},
+					Extra:    []*models.Schema{},
+					Modified: []*SchemaChange{},
+				},
+			},
+			wantStr: []string{"source", "target", "No differences found"},
+		},
+		{
+			name: "with schema differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing: []*models.Schema{{Name: "schema1"}},
+					Extra:   []*models.Schema{{Name: "schema2"}},
+					Modified: []*SchemaChange{
+						{Name: "public"},
+					},
+				},
+			},
+			wantStr: []string{"Schemas:", "Missing:  1", "Extra:    1", "Modified: 1"},
+		},
+		{
+			name: "with table differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Modified: []*SchemaChange{
+						{
+							Name: "public",
+							Tables: &TableDiff{
+								Missing: []*models.Table{{Name: "users"}},
+								Extra:   []*models.Table{{Name: "posts"}},
+								Modified: []*TableChange{
+									{Name: "comments", Schema: "public"},
+								},
+							},
+						},
+					},
+				},
+			},
+			wantStr: []string{"Tables:", "Missing:  1", "Extra:    1", "Modified: 1"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			err := formatSummary(tt.result, &buf)
+
+			if err != nil {
+				t.Errorf("formatSummary() error = %v", err)
+				return
+			}
+
+			output := buf.String()
+			for _, want := range tt.wantStr {
+				if !strings.Contains(output, want) {
+					t.Errorf("formatSummary() output doesn't contain %q\nGot: %s", want, output)
+				}
+			}
+		})
+	}
+}
+
+func TestFormatJSON(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Missing:  []*models.Schema{{Name: "schema1"}},
+			Extra:    []*models.Schema{},
+			Modified: []*SchemaChange{},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatJSON(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatJSON() error = %v", err)
+		return
+	}
+
+	// Check if output is valid JSON
+	var decoded DiffResult
+	if err := json.Unmarshal(buf.Bytes(), &decoded); err != nil {
+		t.Errorf("formatJSON() produced invalid JSON: %v", err)
+	}
+
+	// Check basic structure
+	if decoded.Source != "source" {
+		t.Errorf("formatJSON() source = %v, want %v", decoded.Source, "source")
+	}
+	if decoded.Target != "target" {
+		t.Errorf("formatJSON() target = %v, want %v", decoded.Target, "target")
+	}
+	if len(decoded.Schemas.Missing) != 1 {
+		t.Errorf("formatJSON() missing schemas = %v, want 1", len(decoded.Schemas.Missing))
+	}
+}
+
+func TestFormatHTML(t *testing.T) {
+	tests := []struct {
+		name    string
+		result  *DiffResult
+		wantStr []string // HTML elements/content that should appear
+	}{
+		{
+			name: "basic HTML structure",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{},
+					Extra:    []*models.Schema{},
+					Modified: []*SchemaChange{},
+				},
+			},
+			wantStr: []string{
+				"<!DOCTYPE html>",
+				"<title>Database Diff Report</title>",
+				"source",
+				"target",
+			},
+		},
+		{
+			name: "with schema differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{{Name: "missing_schema"}},
+					Extra:    []*models.Schema{{Name: "extra_schema"}},
+					Modified: []*SchemaChange{},
+				},
+			},
+			wantStr: []string{
+				"<!DOCTYPE html>",
+				"missing_schema",
+				"extra_schema",
+				"MISSING",
+				"EXTRA",
+			},
+		},
+		{
+			name: "with table modifications",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Modified: []*SchemaChange{
+						{
+							Name: "public",
+							Tables: &TableDiff{
+								Modified: []*TableChange{
+									{
+										Name:   "users",
+										Schema: "public",
+										Columns: &ColumnDiff{
+											Missing: []*models.Column{{Name: "email", Type: "text"}},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			wantStr: []string{
+				"public",
+				"users",
+				"email",
+				"text",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			err := formatHTML(tt.result, &buf)
+
+			if err != nil {
+				t.Errorf("formatHTML() error = %v", err)
+				return
+			}
+
+			output := buf.String()
+			for _, want := range tt.wantStr {
+				if !strings.Contains(output, want) {
+					t.Errorf("formatHTML() output doesn't contain %q", want)
+				}
+			}
+		})
+	}
+}
+
+func TestFormatSummaryWithColumns(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Modified: []*SchemaChange{
+				{
+					Name: "public",
+					Tables: &TableDiff{
+						Modified: []*TableChange{
+							{
+								Name:   "users",
+								Schema: "public",
+								Columns: &ColumnDiff{
+									Missing: []*models.Column{{Name: "email"}},
+									Extra:   []*models.Column{{Name: "phone"}, {Name: "address"}},
+									Modified: []*ColumnChange{
+										{Name: "name"},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatSummary(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatSummary() error = %v", err)
+		return
+	}
+
+	output := buf.String()
+	wantStrings := []string{
+		"Columns:",
+		"Missing:  1",
+		"Extra:    2",
+		"Modified: 1",
+	}
+
+	for _, want := range wantStrings {
+		if !strings.Contains(output, want) {
+			t.Errorf("formatSummary() output doesn't contain %q\nGot: %s", want, output)
+		}
+	}
+}
+
+func TestFormatSummaryWithIndexes(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Modified: []*SchemaChange{
+				{
+					Name: "public",
+					Tables: &TableDiff{
+						Modified: []*TableChange{
+							{
+								Name:   "users",
+								Schema: "public",
+								Indexes: &IndexDiff{
+									Missing:  []*models.Index{{Name: "idx_email"}},
+									Extra:    []*models.Index{{Name: "idx_phone"}},
+									Modified: []*IndexChange{{Name: "idx_name"}},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatSummary(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatSummary() error = %v", err)
+		return
+	}
+
+	output := buf.String()
+	if !strings.Contains(output, "Indexes:") {
+		t.Error("formatSummary() output doesn't contain Indexes section")
+	}
+	if !strings.Contains(output, "Missing:  1") {
+		t.Error("formatSummary() output doesn't contain correct missing count")
+	}
+}
+
+func TestFormatSummaryWithConstraints(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Modified: []*SchemaChange{
+				{
+					Name: "public",
+					Tables: &TableDiff{
+						Modified: []*TableChange{
+							{
+								Name:   "users",
+								Schema: "public",
+								Constraints: &ConstraintDiff{
+									Missing: []*models.Constraint{{Name: "pk_users", Type: "PRIMARY KEY"}},
+									Extra:   []*models.Constraint{{Name: "fk_users_roles", Type: "FOREIGN KEY"}},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatSummary(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatSummary() error = %v", err)
+		return
+	}
+
+	output := buf.String()
+	if !strings.Contains(output, "Constraints:") {
+		t.Error("formatSummary() output doesn't contain Constraints section")
+	}
+}
+
+func TestFormatJSONIndentation(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Missing: []*models.Schema{{Name: "test"}},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatJSON(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatJSON() error = %v", err)
+		return
+	}
+
+	// Check that JSON is indented (has newlines and spaces)
+	output := buf.String()
+	if !strings.Contains(output, "\n") {
+		t.Error("formatJSON() should produce indented JSON with newlines")
+	}
+	if !strings.Contains(output, "  ") {
+		t.Error("formatJSON() should produce indented JSON with spaces")
+	}
+}
+
+func TestOutputFormatConstants(t *testing.T) {
+	tests := []struct {
+		name   string
+		format OutputFormat
+		want   string
+	}{
+		{"summary constant", FormatSummary, "summary"},
+		{"json constant", FormatJSON, "json"},
+		{"html constant", FormatHTML, "html"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if string(tt.format) != tt.want {
+				t.Errorf("OutputFormat %v = %v, want %v", tt.name, tt.format, tt.want)
+			}
+		})
+	}
+}

pkg/inspector/inspector_test.go

@@ -0,0 +1,238 @@
+package inspector
+
+import (
+	"testing"
+)
+
+func TestNewInspector(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	inspector := NewInspector(db, config)
+
+	if inspector == nil {
+		t.Fatal("NewInspector() returned nil")
+	}
+
+	if inspector.db != db {
+		t.Error("NewInspector() database not set correctly")
+	}
+
+	if inspector.config != config {
+		t.Error("NewInspector() config not set correctly")
+	}
+}
+
+func TestInspect(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	inspector := NewInspector(db, config)
+	report, err := inspector.Inspect()
+
+	if err != nil {
+		t.Fatalf("Inspect() returned error: %v", err)
+	}
+
+	if report == nil {
+		t.Fatal("Inspect() returned nil report")
+	}
+
+	if report.Database != db.Name {
+		t.Errorf("Inspect() report.Database = %q, want %q", report.Database, db.Name)
+	}
+
+	if report.Summary.TotalRules != len(config.Rules) {
+		t.Errorf("Inspect() TotalRules = %d, want %d", report.Summary.TotalRules, len(config.Rules))
+	}
+
+	if len(report.Violations) == 0 {
+		t.Error("Inspect() returned no violations, expected some results")
+	}
+}
+
+func TestInspectWithDisabledRules(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	// Disable all rules
+	for name := range config.Rules {
+		rule := config.Rules[name]
+		rule.Enabled = "off"
+		config.Rules[name] = rule
+	}
+
+	inspector := NewInspector(db, config)
+	report, err := inspector.Inspect()
+
+	if err != nil {
+		t.Fatalf("Inspect() with disabled rules returned error: %v", err)
+	}
+
+	if report.Summary.RulesChecked != 0 {
+		t.Errorf("Inspect() RulesChecked = %d, want 0 (all disabled)", report.Summary.RulesChecked)
+	}
+
+	if report.Summary.RulesSkipped != len(config.Rules) {
+		t.Errorf("Inspect() RulesSkipped = %d, want %d", report.Summary.RulesSkipped, len(config.Rules))
+	}
+}
+
+func TestInspectWithEnforcedRules(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	// Enable only one rule and enforce it
+	for name := range config.Rules {
+		rule := config.Rules[name]
+		rule.Enabled = "off"
+		config.Rules[name] = rule
+	}
+
+	primaryKeyRule := config.Rules["primary_key_naming"]
+	primaryKeyRule.Enabled = "enforce"
+	primaryKeyRule.Pattern = "^id$"
+	config.Rules["primary_key_naming"] = primaryKeyRule
+
+	inspector := NewInspector(db, config)
+	report, err := inspector.Inspect()
+
+	if err != nil {
+		t.Fatalf("Inspect() returned error: %v", err)
+	}
+
+	if report.Summary.RulesChecked != 1 {
+		t.Errorf("Inspect() RulesChecked = %d, want 1", report.Summary.RulesChecked)
+	}
+
+	// All results should be at error level for enforced rules
+	for _, violation := range report.Violations {
+		if violation.Level != "error" {
+			t.Errorf("Enforced rule violation has Level = %q, want \"error\"", violation.Level)
+		}
+	}
+}
+
+func TestGenerateSummary(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+	inspector := NewInspector(db, config)
+
+	results := []ValidationResult{
+		{RuleName: "rule1", Passed: true, Level: "error"},
+		{RuleName: "rule2", Passed: false, Level: "error"},
+		{RuleName: "rule3", Passed: false, Level: "warning"},
+		{RuleName: "rule4", Passed: true, Level: "warning"},
+	}
+
+	summary := inspector.generateSummary(results)
+
+	if summary.PassedCount != 2 {
+		t.Errorf("generateSummary() PassedCount = %d, want 2", summary.PassedCount)
+	}
+
+	if summary.ErrorCount != 1 {
+		t.Errorf("generateSummary() ErrorCount = %d, want 1", summary.ErrorCount)
+	}
+
+	if summary.WarningCount != 1 {
+		t.Errorf("generateSummary() WarningCount = %d, want 1", summary.WarningCount)
+	}
+}
+
+func TestHasErrors(t *testing.T) {
+	tests := []struct {
+		name   string
+		report *InspectorReport
+		want   bool
+	}{
+		{
+			name: "with errors",
+			report: &InspectorReport{
+				Summary: ReportSummary{
+					ErrorCount: 5,
+				},
+			},
+			want: true,
+		},
+		{
+			name: "without errors",
+			report: &InspectorReport{
+				Summary: ReportSummary{
+					ErrorCount:   0,
+					WarningCount: 3,
+				},
+			},
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.report.HasErrors(); got != tt.want {
+				t.Errorf("HasErrors() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetValidator(t *testing.T) {
+	tests := []struct {
+		name         string
+		functionName string
+		wantExists   bool
+	}{
+		{"primary_key_naming", "primary_key_naming", true},
+		{"primary_key_datatype", "primary_key_datatype", true},
+		{"foreign_key_column_naming", "foreign_key_column_naming", true},
+		{"table_regexpr", "table_regexpr", true},
+		{"column_regexpr", "column_regexpr", true},
+		{"reserved_words", "reserved_words", true},
+		{"have_primary_key", "have_primary_key", true},
+		{"orphaned_foreign_key", "orphaned_foreign_key", true},
+		{"circular_dependency", "circular_dependency", true},
+		{"unknown_function", "unknown_function", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, exists := getValidator(tt.functionName)
+			if exists != tt.wantExists {
+				t.Errorf("getValidator(%q) exists = %v, want %v", tt.functionName, exists, tt.wantExists)
+			}
+		})
+	}
+}
+
+func TestCreateResult(t *testing.T) {
+	result := createResult(
+		"test_rule",
+		true,
+		"Test message",
+		"schema.table.column",
+		map[string]interface{}{
+			"key1": "value1",
+			"key2": 42,
+		},
+	)
+
+	if result.RuleName != "test_rule" {
+		t.Errorf("createResult() RuleName = %q, want \"test_rule\"", result.RuleName)
+	}
+
+	if !result.Passed {
+		t.Error("createResult() Passed = false, want true")
+	}
+
+	if result.Message != "Test message" {
+		t.Errorf("createResult() Message = %q, want \"Test message\"", result.Message)
+	}
+
+	if result.Location != "schema.table.column" {
+		t.Errorf("createResult() Location = %q, want \"schema.table.column\"", result.Location)
+	}
+
+	if len(result.Context) != 2 {
+		t.Errorf("createResult() Context length = %d, want 2", len(result.Context))
+	}
+}

pkg/inspector/report_test.go

@@ -0,0 +1,366 @@
+package inspector
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+)
+
+func createTestReport() *InspectorReport {
+	return &InspectorReport{
+		Summary: ReportSummary{
+			TotalRules:   10,
+			RulesChecked: 8,
+			RulesSkipped: 2,
+			ErrorCount:   3,
+			WarningCount: 5,
+			PassedCount:  12,
+		},
+		Violations: []ValidationResult{
+			{
+				RuleName: "primary_key_naming",
+				Level:    "error",
+				Message:  "Primary key should start with 'id_'",
+				Location: "public.users.user_id",
+				Passed:   false,
+				Context: map[string]interface{}{
+					"schema":  "public",
+					"table":   "users",
+					"column":  "user_id",
+					"pattern": "^id_",
+				},
+			},
+			{
+				RuleName: "table_name_length",
+				Level:    "warning",
+				Message:  "Table name too long",
+				Location: "public.very_long_table_name_that_exceeds_limits",
+				Passed:   false,
+				Context: map[string]interface{}{
+					"schema":     "public",
+					"table":      "very_long_table_name_that_exceeds_limits",
+					"length":     44,
+					"max_length": 32,
+				},
+			},
+		},
+		GeneratedAt:  time.Now(),
+		Database:     "testdb",
+		SourceFormat: "postgresql",
+	}
+}
+
+func TestNewMarkdownFormatter(t *testing.T) {
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	if formatter == nil {
+		t.Fatal("NewMarkdownFormatter() returned nil")
+	}
+
+	// Buffer is not a terminal, so colors should be disabled
+	if formatter.UseColors {
+		t.Error("NewMarkdownFormatter() UseColors should be false for non-terminal")
+	}
+}
+
+func TestNewJSONFormatter(t *testing.T) {
+	formatter := NewJSONFormatter()
+
+	if formatter == nil {
+		t.Fatal("NewJSONFormatter() returned nil")
+	}
+}
+
+func TestMarkdownFormatter_Format(t *testing.T) {
+	report := createTestReport()
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	output, err := formatter.Format(report)
+	if err != nil {
+		t.Fatalf("MarkdownFormatter.Format() returned error: %v", err)
+	}
+
+	// Check that output contains expected sections
+	if !strings.Contains(output, "# RelSpec Inspector Report") {
+		t.Error("Markdown output missing header")
+	}
+
+	if !strings.Contains(output, "Database:") {
+		t.Error("Markdown output missing database field")
+	}
+
+	if !strings.Contains(output, "testdb") {
+		t.Error("Markdown output missing database name")
+	}
+
+	if !strings.Contains(output, "Summary") {
+		t.Error("Markdown output missing summary section")
+	}
+
+	if !strings.Contains(output, "Rules Checked: 8") {
+		t.Error("Markdown output missing rules checked count")
+	}
+
+	if !strings.Contains(output, "Errors: 3") {
+		t.Error("Markdown output missing error count")
+	}
+
+	if !strings.Contains(output, "Warnings: 5") {
+		t.Error("Markdown output missing warning count")
+	}
+
+	if !strings.Contains(output, "Violations") {
+		t.Error("Markdown output missing violations section")
+	}
+
+	if !strings.Contains(output, "primary_key_naming") {
+		t.Error("Markdown output missing rule name")
+	}
+
+	if !strings.Contains(output, "public.users.user_id") {
+		t.Error("Markdown output missing location")
+	}
+}
+
+func TestMarkdownFormatter_FormatNoViolations(t *testing.T) {
+	report := &InspectorReport{
+		Summary: ReportSummary{
+			TotalRules:   10,
+			RulesChecked: 10,
+			RulesSkipped: 0,
+			ErrorCount:   0,
+			WarningCount: 0,
+			PassedCount:  50,
+		},
+		Violations:   []ValidationResult{},
+		GeneratedAt:  time.Now(),
+		Database:     "testdb",
+		SourceFormat: "postgresql",
+	}
+
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	output, err := formatter.Format(report)
+	if err != nil {
+		t.Fatalf("MarkdownFormatter.Format() returned error: %v", err)
+	}
+
+	if !strings.Contains(output, "No violations found") {
+		t.Error("Markdown output should indicate no violations")
+	}
+}
+
+func TestJSONFormatter_Format(t *testing.T) {
+	report := createTestReport()
+	formatter := NewJSONFormatter()
+
+	output, err := formatter.Format(report)
+	if err != nil {
+		t.Fatalf("JSONFormatter.Format() returned error: %v", err)
+	}
+
+	// Verify it's valid JSON
+	var decoded InspectorReport
+	if err := json.Unmarshal([]byte(output), &decoded); err != nil {
+		t.Fatalf("JSONFormatter.Format() produced invalid JSON: %v", err)
+	}
+
+	// Check key fields
+	if decoded.Database != "testdb" {
+		t.Errorf("JSON decoded Database = %q, want \"testdb\"", decoded.Database)
+	}
+
+	if decoded.Summary.ErrorCount != 3 {
+		t.Errorf("JSON decoded ErrorCount = %d, want 3", decoded.Summary.ErrorCount)
+	}
+
+	if len(decoded.Violations) != 2 {
+		t.Errorf("JSON decoded Violations length = %d, want 2", len(decoded.Violations))
+	}
+}
+
+func TestMarkdownFormatter_FormatHeader(t *testing.T) {
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	header := formatter.formatHeader("Test Header")
+
+	if !strings.Contains(header, "# Test Header") {
+		t.Errorf("formatHeader() = %q, want to contain \"# Test Header\"", header)
+	}
+}
+
+func TestMarkdownFormatter_FormatBold(t *testing.T) {
+	tests := []struct {
+		name         string
+		useColors    bool
+		text         string
+		wantContains string
+	}{
+		{
+			name:         "without colors",
+			useColors:    false,
+			text:         "Bold Text",
+			wantContains: "**Bold Text**",
+		},
+		{
+			name:         "with colors",
+			useColors:    true,
+			text:         "Bold Text",
+			wantContains: "Bold Text",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			formatter := &MarkdownFormatter{UseColors: tt.useColors}
+			result := formatter.formatBold(tt.text)
+
+			if !strings.Contains(result, tt.wantContains) {
+				t.Errorf("formatBold() = %q, want to contain %q", result, tt.wantContains)
+			}
+		})
+	}
+}
+
+func TestMarkdownFormatter_Colorize(t *testing.T) {
+	tests := []struct {
+		name      string
+		useColors bool
+		text      string
+		color     string
+		wantColor bool
+	}{
+		{
+			name:      "without colors",
+			useColors: false,
+			text:      "Test",
+			color:     colorRed,
+			wantColor: false,
+		},
+		{
+			name:      "with colors",
+			useColors: true,
+			text:      "Test",
+			color:     colorRed,
+			wantColor: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			formatter := &MarkdownFormatter{UseColors: tt.useColors}
+			result := formatter.colorize(tt.text, tt.color)
+
+			hasColor := strings.Contains(result, tt.color)
+			if hasColor != tt.wantColor {
+				t.Errorf("colorize() has color codes = %v, want %v", hasColor, tt.wantColor)
+			}
+
+			if !strings.Contains(result, tt.text) {
+				t.Errorf("colorize() doesn't contain original text %q", tt.text)
+			}
+		})
+	}
+}
+
+func TestMarkdownFormatter_FormatContext(t *testing.T) {
+	formatter := &MarkdownFormatter{UseColors: false}
+
+	context := map[string]interface{}{
+		"schema":     "public",
+		"table":      "users",
+		"column":     "id",
+		"pattern":    "^id_",
+		"max_length": 64,
+	}
+
+	result := formatter.formatContext(context)
+
+	// Should not include schema, table, column (they're in location)
+	if strings.Contains(result, "schema") {
+		t.Error("formatContext() should skip schema field")
+	}
+
+	if strings.Contains(result, "table=") {
+		t.Error("formatContext() should skip table field")
+	}
+
+	if strings.Contains(result, "column=") {
+		t.Error("formatContext() should skip column field")
+	}
+
+	// Should include other fields
+	if !strings.Contains(result, "pattern") {
+		t.Error("formatContext() should include pattern field")
+	}
+
+	if !strings.Contains(result, "max_length") {
+		t.Error("formatContext() should include max_length field")
+	}
+}
+
+func TestMarkdownFormatter_FormatViolation(t *testing.T) {
+	formatter := &MarkdownFormatter{UseColors: false}
+
+	violation := ValidationResult{
+		RuleName: "test_rule",
+		Level:    "error",
+		Message:  "Test violation message",
+		Location: "public.users.id",
+		Passed:   false,
+		Context: map[string]interface{}{
+			"pattern": "^id_",
+		},
+	}
+
+	result := formatter.formatViolation(violation, colorRed)
+
+	if !strings.Contains(result, "test_rule") {
+		t.Error("formatViolation() should include rule name")
+	}
+
+	if !strings.Contains(result, "Test violation message") {
+		t.Error("formatViolation() should include message")
+	}
+
+	if !strings.Contains(result, "public.users.id") {
+		t.Error("formatViolation() should include location")
+	}
+
+	if !strings.Contains(result, "Location:") {
+		t.Error("formatViolation() should include Location label")
+	}
+
+	if !strings.Contains(result, "Message:") {
+		t.Error("formatViolation() should include Message label")
+	}
+}
+
+func TestReportFormatConstants(t *testing.T) {
+	// Test that color constants are defined
+	if colorReset == "" {
+		t.Error("colorReset is not defined")
+	}
+
+	if colorRed == "" {
+		t.Error("colorRed is not defined")
+	}
+
+	if colorYellow == "" {
+		t.Error("colorYellow is not defined")
+	}
+
+	if colorGreen == "" {
+		t.Error("colorGreen is not defined")
+	}
+
+	if colorBold == "" {
+		t.Error("colorBold is not defined")
+	}
+}

pkg/inspector/rules_test.go

@@ -0,0 +1,249 @@
+package inspector
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestGetDefaultConfig(t *testing.T) {
+	config := GetDefaultConfig()
+
+	if config == nil {
+		t.Fatal("GetDefaultConfig() returned nil")
+	}
+
+	if config.Version != "1.0" {
+		t.Errorf("GetDefaultConfig() Version = %q, want \"1.0\"", config.Version)
+	}
+
+	if len(config.Rules) == 0 {
+		t.Error("GetDefaultConfig() returned no rules")
+	}
+
+	// Check that all expected rules are present
+	expectedRules := []string{
+		"primary_key_naming",
+		"primary_key_datatype",
+		"primary_key_auto_increment",
+		"foreign_key_column_naming",
+		"foreign_key_constraint_naming",
+		"foreign_key_index",
+		"table_naming_case",
+		"column_naming_case",
+		"table_name_length",
+		"column_name_length",
+		"reserved_keywords",
+		"missing_primary_key",
+		"orphaned_foreign_key",
+		"circular_dependency",
+	}
+
+	for _, ruleName := range expectedRules {
+		if _, exists := config.Rules[ruleName]; !exists {
+			t.Errorf("GetDefaultConfig() missing rule: %q", ruleName)
+		}
+	}
+}
+
+func TestLoadConfig_NonExistentFile(t *testing.T) {
+	// Try to load a non-existent file
+	config, err := LoadConfig("/path/to/nonexistent/file.yaml")
+
+	if err != nil {
+		t.Fatalf("LoadConfig() with non-existent file returned error: %v", err)
+	}
+
+	// Should return default config
+	if config == nil {
+		t.Fatal("LoadConfig() returned nil config for non-existent file")
+	}
+
+	if len(config.Rules) == 0 {
+		t.Error("LoadConfig() returned config with no rules")
+	}
+}
+
+func TestLoadConfig_ValidFile(t *testing.T) {
+	// Create a temporary config file
+	tmpDir := t.TempDir()
+	configPath := filepath.Join(tmpDir, "test-config.yaml")
+
+	configContent := `version: "1.0"
+rules:
+  primary_key_naming:
+    enabled: "enforce"
+    function: "primary_key_naming"
+    pattern: "^pk_"
+    message: "Primary keys must start with pk_"
+  table_name_length:
+    enabled: "warn"
+    function: "table_name_length"
+    max_length: 50
+    message: "Table name too long"
+`
+
+	err := os.WriteFile(configPath, []byte(configContent), 0644)
+	if err != nil {
+		t.Fatalf("Failed to create test config file: %v", err)
+	}
+
+	config, err := LoadConfig(configPath)
+	if err != nil {
+		t.Fatalf("LoadConfig() returned error: %v", err)
+	}
+
+	if config.Version != "1.0" {
+		t.Errorf("LoadConfig() Version = %q, want \"1.0\"", config.Version)
+	}
+
+	if len(config.Rules) != 2 {
+		t.Errorf("LoadConfig() loaded %d rules, want 2", len(config.Rules))
+	}
+
+	// Check primary_key_naming rule
+	pkRule, exists := config.Rules["primary_key_naming"]
+	if !exists {
+		t.Fatal("LoadConfig() missing primary_key_naming rule")
+	}
+
+	if pkRule.Enabled != "enforce" {
+		t.Errorf("primary_key_naming.Enabled = %q, want \"enforce\"", pkRule.Enabled)
+	}
+
+	if pkRule.Pattern != "^pk_" {
+		t.Errorf("primary_key_naming.Pattern = %q, want \"^pk_\"", pkRule.Pattern)
+	}
+
+	// Check table_name_length rule
+	lengthRule, exists := config.Rules["table_name_length"]
+	if !exists {
+		t.Fatal("LoadConfig() missing table_name_length rule")
+	}
+
+	if lengthRule.MaxLength != 50 {
+		t.Errorf("table_name_length.MaxLength = %d, want 50", lengthRule.MaxLength)
+	}
+}
+
+func TestLoadConfig_InvalidYAML(t *testing.T) {
+	// Create a temporary invalid config file
+	tmpDir := t.TempDir()
+	configPath := filepath.Join(tmpDir, "invalid-config.yaml")
+
+	invalidContent := `invalid: yaml: content: {[}]`
+
+	err := os.WriteFile(configPath, []byte(invalidContent), 0644)
+	if err != nil {
+		t.Fatalf("Failed to create test config file: %v", err)
+	}
+
+	_, err = LoadConfig(configPath)
+	if err == nil {
+		t.Error("LoadConfig() with invalid YAML did not return error")
+	}
+}
+
+func TestRuleIsEnabled(t *testing.T) {
+	tests := []struct {
+		name string
+		rule Rule
+		want bool
+	}{
+		{
+			name: "enforce is enabled",
+			rule: Rule{Enabled: "enforce"},
+			want: true,
+		},
+		{
+			name: "warn is enabled",
+			rule: Rule{Enabled: "warn"},
+			want: true,
+		},
+		{
+			name: "off is not enabled",
+			rule: Rule{Enabled: "off"},
+			want: false,
+		},
+		{
+			name: "empty is not enabled",
+			rule: Rule{Enabled: ""},
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.rule.IsEnabled(); got != tt.want {
+				t.Errorf("Rule.IsEnabled() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRuleIsEnforced(t *testing.T) {
+	tests := []struct {
+		name string
+		rule Rule
+		want bool
+	}{
+		{
+			name: "enforce is enforced",
+			rule: Rule{Enabled: "enforce"},
+			want: true,
+		},
+		{
+			name: "warn is not enforced",
+			rule: Rule{Enabled: "warn"},
+			want: false,
+		},
+		{
+			name: "off is not enforced",
+			rule: Rule{Enabled: "off"},
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.rule.IsEnforced(); got != tt.want {
+				t.Errorf("Rule.IsEnforced() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDefaultConfigRuleSettings(t *testing.T) {
+	config := GetDefaultConfig()
+
+	// Test specific rule settings
+	pkNamingRule := config.Rules["primary_key_naming"]
+	if pkNamingRule.Function != "primary_key_naming" {
+		t.Errorf("primary_key_naming.Function = %q, want \"primary_key_naming\"", pkNamingRule.Function)
+	}
+
+	if pkNamingRule.Pattern != "^id_" {
+		t.Errorf("primary_key_naming.Pattern = %q, want \"^id_\"", pkNamingRule.Pattern)
+	}
+
+	// Test datatype rule
+	pkDatatypeRule := config.Rules["primary_key_datatype"]
+	if len(pkDatatypeRule.AllowedTypes) == 0 {
+		t.Error("primary_key_datatype has no allowed types")
+	}
+
+	// Test length rule
+	tableLengthRule := config.Rules["table_name_length"]
+	if tableLengthRule.MaxLength != 64 {
+		t.Errorf("table_name_length.MaxLength = %d, want 64", tableLengthRule.MaxLength)
+	}
+
+	// Test reserved keywords rule
+	reservedRule := config.Rules["reserved_keywords"]
+	if !reservedRule.CheckTables {
+		t.Error("reserved_keywords.CheckTables should be true")
+	}
+	if !reservedRule.CheckColumns {
+		t.Error("reserved_keywords.CheckColumns should be true")
+	}
+}

pkg/inspector/validators_test.go

@@ -0,0 +1,837 @@
+package inspector
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// Helper function to create test database
+func createTestDatabase() *models.Database {
+	return &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "users",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:          "id",
+								Type:          "bigserial",
+								IsPrimaryKey:  true,
+								AutoIncrement: true,
+							},
+							"username": {
+								Name:         "username",
+								Type:         "varchar(50)",
+								NotNull:      true,
+								IsPrimaryKey: false,
+							},
+							"rid_organization": {
+								Name:         "rid_organization",
+								Type:         "bigint",
+								NotNull:      true,
+								IsPrimaryKey: false,
+							},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_users_organization": {
+								Name:              "fk_users_organization",
+								Type:              models.ForeignKeyConstraint,
+								Columns:           []string{"rid_organization"},
+								ReferencedTable:   "organizations",
+								ReferencedSchema:  "public",
+								ReferencedColumns: []string{"id"},
+							},
+						},
+						Indexes: map[string]*models.Index{
+							"idx_rid_organization": {
+								Name:    "idx_rid_organization",
+								Columns: []string{"rid_organization"},
+							},
+						},
+					},
+					{
+						Name: "organizations",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:          "id",
+								Type:          "bigserial",
+								IsPrimaryKey:  true,
+								AutoIncrement: true,
+							},
+							"name": {
+								Name:         "name",
+								Type:         "varchar(100)",
+								NotNull:      true,
+								IsPrimaryKey: false,
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func TestValidatePrimaryKeyNaming(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "matching pattern id",
+			rule: Rule{
+				Pattern: "^id$",
+				Message: "Primary key should be 'id'",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "non-matching pattern id_",
+			rule: Rule{
+				Pattern: "^id_",
+				Message: "Primary key should start with 'id_'",
+			},
+			wantLen:  2,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validatePrimaryKeyNaming(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validatePrimaryKeyNaming() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validatePrimaryKeyNaming() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidatePrimaryKeyDatatype(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "allowed type bigserial",
+			rule: Rule{
+				AllowedTypes: []string{"bigserial", "bigint", "int"},
+				Message:      "Primary key should use integer types",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "disallowed type",
+			rule: Rule{
+				AllowedTypes: []string{"uuid"},
+				Message:      "Primary key should use UUID",
+			},
+			wantLen:  2,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validatePrimaryKeyDatatype(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validatePrimaryKeyDatatype() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validatePrimaryKeyDatatype() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidatePrimaryKeyAutoIncrement(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name    string
+		rule    Rule
+		wantLen int
+	}{
+		{
+			name: "require auto increment",
+			rule: Rule{
+				RequireAutoIncrement: true,
+				Message:              "Primary key should have auto-increment",
+			},
+			wantLen: 0, // No violations - all PKs have auto-increment
+		},
+		{
+			name: "disallow auto increment",
+			rule: Rule{
+				RequireAutoIncrement: false,
+				Message:              "Primary key should not have auto-increment",
+			},
+			wantLen: 2, // 2 violations - both PKs have auto-increment
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validatePrimaryKeyAutoIncrement(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validatePrimaryKeyAutoIncrement() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateForeignKeyColumnNaming(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "matching pattern rid_",
+			rule: Rule{
+				Pattern: "^rid_",
+				Message: "Foreign key columns should start with 'rid_'",
+			},
+			wantLen:  1,
+			wantPass: true,
+		},
+		{
+			name: "non-matching pattern fk_",
+			rule: Rule{
+				Pattern: "^fk_",
+				Message: "Foreign key columns should start with 'fk_'",
+			},
+			wantLen:  1,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateForeignKeyColumnNaming(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateForeignKeyColumnNaming() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateForeignKeyColumnNaming() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateForeignKeyConstraintNaming(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "matching pattern fk_",
+			rule: Rule{
+				Pattern: "^fk_",
+				Message: "Foreign key constraints should start with 'fk_'",
+			},
+			wantLen:  1,
+			wantPass: true,
+		},
+		{
+			name: "non-matching pattern FK_",
+			rule: Rule{
+				Pattern: "^FK_",
+				Message: "Foreign key constraints should start with 'FK_'",
+			},
+			wantLen:  1,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateForeignKeyConstraintNaming(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateForeignKeyConstraintNaming() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateForeignKeyConstraintNaming() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateForeignKeyIndex(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "require index with index present",
+			rule: Rule{
+				RequireIndex: true,
+				Message:      "Foreign key columns should have indexes",
+			},
+			wantLen:  1,
+			wantPass: true,
+		},
+		{
+			name: "no requirement",
+			rule: Rule{
+				RequireIndex: false,
+				Message:      "Foreign key index check disabled",
+			},
+			wantLen:  0,
+			wantPass: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateForeignKeyIndex(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateForeignKeyIndex() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateForeignKeyIndex() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateTableNamingCase(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "lowercase snake_case pattern",
+			rule: Rule{
+				Pattern: "^[a-z][a-z0-9_]*$",
+				Case:    "lowercase",
+				Message: "Table names should be lowercase snake_case",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "uppercase pattern",
+			rule: Rule{
+				Pattern: "^[A-Z][A-Z0-9_]*$",
+				Case:    "uppercase",
+				Message: "Table names should be uppercase",
+			},
+			wantLen:  2,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateTableNamingCase(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateTableNamingCase() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateTableNamingCase() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateColumnNamingCase(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "lowercase snake_case pattern",
+			rule: Rule{
+				Pattern: "^[a-z][a-z0-9_]*$",
+				Case:    "lowercase",
+				Message: "Column names should be lowercase snake_case",
+			},
+			wantLen:  5, // 5 total columns across both tables
+			wantPass: true,
+		},
+		{
+			name: "camelCase pattern",
+			rule: Rule{
+				Pattern: "^[a-z][a-zA-Z0-9]*$",
+				Case:    "camelCase",
+				Message: "Column names should be camelCase",
+			},
+			wantLen:  5,
+			wantPass: false, // rid_organization has underscore
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateColumnNamingCase(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateColumnNamingCase() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateTableNameLength(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "max length 64",
+			rule: Rule{
+				MaxLength: 64,
+				Message:   "Table name too long",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "max length 5",
+			rule: Rule{
+				MaxLength: 5,
+				Message:   "Table name too long",
+			},
+			wantLen:  2,
+			wantPass: false, // "users" is 5 chars (passes), "organizations" is 13 (fails)
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateTableNameLength(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateTableNameLength() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateColumnNameLength(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "max length 64",
+			rule: Rule{
+				MaxLength: 64,
+				Message:   "Column name too long",
+			},
+			wantLen:  5,
+			wantPass: true,
+		},
+		{
+			name: "max length 5",
+			rule: Rule{
+				MaxLength: 5,
+				Message:   "Column name too long",
+			},
+			wantLen:  5,
+			wantPass: false, // Some columns exceed 5 chars
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateColumnNameLength(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateColumnNameLength() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateReservedKeywords(t *testing.T) {
+	// Create a database with reserved keywords
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "user", // "user" is a reserved keyword
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "bigint",
+								IsPrimaryKey: true,
+							},
+							"select": { // "select" is a reserved keyword
+								Name: "select",
+								Type: "varchar(50)",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	tests := []struct {
+		name        string
+		rule        Rule
+		wantLen     int
+		checkPasses bool
+	}{
+		{
+			name: "check tables only",
+			rule: Rule{
+				CheckTables:  true,
+				CheckColumns: false,
+				Message:      "Reserved keyword used",
+			},
+			wantLen:     1, // "user" table
+			checkPasses: false,
+		},
+		{
+			name: "check columns only",
+			rule: Rule{
+				CheckTables:  false,
+				CheckColumns: true,
+				Message:      "Reserved keyword used",
+			},
+			wantLen:     2, // "id", "select" columns (id passes, select fails)
+			checkPasses: false,
+		},
+		{
+			name: "check both",
+			rule: Rule{
+				CheckTables:  true,
+				CheckColumns: true,
+				Message:      "Reserved keyword used",
+			},
+			wantLen:     3, // "user" table + "id", "select" columns
+			checkPasses: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateReservedKeywords(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateReservedKeywords() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateMissingPrimaryKey(t *testing.T) {
+	// Create database with and without primary keys
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "with_pk",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "bigint",
+								IsPrimaryKey: true,
+							},
+						},
+					},
+					{
+						Name: "without_pk",
+						Columns: map[string]*models.Column{
+							"name": {
+								Name: "name",
+								Type: "varchar(50)",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	rule := Rule{
+		Message: "Table missing primary key",
+	}
+
+	results := validateMissingPrimaryKey(db, rule, "test_rule")
+
+	if len(results) != 2 {
+		t.Errorf("validateMissingPrimaryKey() returned %d results, want 2", len(results))
+	}
+
+	// First result should pass (with_pk has PK)
+	if results[0].Passed != true {
+		t.Errorf("validateMissingPrimaryKey() result[0].Passed=%v, want true", results[0].Passed)
+	}
+
+	// Second result should fail (without_pk missing PK)
+	if results[1].Passed != false {
+		t.Errorf("validateMissingPrimaryKey() result[1].Passed=%v, want false", results[1].Passed)
+	}
+}
+
+func TestValidateOrphanedForeignKey(t *testing.T) {
+	// Create database with orphaned FK
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "users",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "bigint",
+								IsPrimaryKey: true,
+							},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_nonexistent": {
+								Name:             "fk_nonexistent",
+								Type:             models.ForeignKeyConstraint,
+								Columns:          []string{"rid_organization"},
+								ReferencedTable:  "nonexistent_table",
+								ReferencedSchema: "public",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	rule := Rule{
+		Message: "Foreign key references non-existent table",
+	}
+
+	results := validateOrphanedForeignKey(db, rule, "test_rule")
+
+	if len(results) != 1 {
+		t.Errorf("validateOrphanedForeignKey() returned %d results, want 1", len(results))
+	}
+
+	if results[0].Passed != false {
+		t.Errorf("validateOrphanedForeignKey() passed=%v, want false", results[0].Passed)
+	}
+}
+
+func TestValidateCircularDependency(t *testing.T) {
+	// Create database with circular dependency
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "table_a",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "bigint", IsPrimaryKey: true},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_to_b": {
+								Name:             "fk_to_b",
+								Type:             models.ForeignKeyConstraint,
+								ReferencedTable:  "table_b",
+								ReferencedSchema: "public",
+							},
+						},
+					},
+					{
+						Name: "table_b",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "bigint", IsPrimaryKey: true},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_to_a": {
+								Name:             "fk_to_a",
+								Type:             models.ForeignKeyConstraint,
+								ReferencedTable:  "table_a",
+								ReferencedSchema: "public",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	rule := Rule{
+		Message: "Circular dependency detected",
+	}
+
+	results := validateCircularDependency(db, rule, "test_rule")
+
+	// Should detect circular dependency in both tables
+	if len(results) == 0 {
+		t.Error("validateCircularDependency() returned 0 results, expected circular dependency detection")
+	}
+
+	for _, result := range results {
+		if result.Passed {
+			t.Error("validateCircularDependency() passed=true, want false for circular dependency")
+		}
+	}
+}
+
+func TestNormalizeDataType(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"varchar(50)", "varchar"},
+		{"decimal(10,2)", "decimal"},
+		{"int", "int"},
+		{"BIGINT", "bigint"},
+		{"VARCHAR(255)", "varchar"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			result := normalizeDataType(tt.input)
+			if result != tt.expected {
+				t.Errorf("normalizeDataType(%q) = %q, want %q", tt.input, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestContains(t *testing.T) {
+	tests := []struct {
+		name     string
+		slice    []string
+		value    string
+		expected bool
+	}{
+		{"found exact", []string{"foo", "bar", "baz"}, "bar", true},
+		{"not found", []string{"foo", "bar", "baz"}, "qux", false},
+		{"case insensitive match", []string{"foo", "Bar", "baz"}, "bar", true},
+		{"empty slice", []string{}, "foo", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := contains(tt.slice, tt.value)
+			if result != tt.expected {
+				t.Errorf("contains(%v, %q) = %v, want %v", tt.slice, tt.value, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestHasCycle(t *testing.T) {
+	tests := []struct {
+		name     string
+		graph    map[string][]string
+		node     string
+		expected bool
+	}{
+		{
+			name: "simple cycle",
+			graph: map[string][]string{
+				"A": {"B"},
+				"B": {"C"},
+				"C": {"A"},
+			},
+			node:     "A",
+			expected: true,
+		},
+		{
+			name: "no cycle",
+			graph: map[string][]string{
+				"A": {"B"},
+				"B": {"C"},
+				"C": {},
+			},
+			node:     "A",
+			expected: false,
+		},
+		{
+			name: "self cycle",
+			graph: map[string][]string{
+				"A": {"A"},
+			},
+			node:     "A",
+			expected: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			visited := make(map[string]bool)
+			recStack := make(map[string]bool)
+			result := hasCycle(tt.node, tt.graph, visited, recStack)
+			if result != tt.expected {
+				t.Errorf("hasCycle() = %v, want %v", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestFormatLocation(t *testing.T) {
+	tests := []struct {
+		schema   string
+		table    string
+		column   string
+		expected string
+	}{
+		{"public", "users", "id", "public.users.id"},
+		{"public", "users", "", "public.users"},
+		{"public", "", "", "public"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.expected, func(t *testing.T) {
+			result := formatLocation(tt.schema, tt.table, tt.column)
+			if result != tt.expected {
+				t.Errorf("formatLocation(%q, %q, %q) = %q, want %q",
+					tt.schema, tt.table, tt.column, result, tt.expected)
+			}
+		})
+	}
+}

pkg/merge/merge.go

@@ -12,14 +12,16 @@ import (
 
 // MergeResult represents the result of a merge operation
 type MergeResult struct {
-	SchemasAdded   int
-	TablesAdded    int
-	ColumnsAdded   int
-	RelationsAdded int
-	DomainsAdded   int
-	EnumsAdded     int
-	ViewsAdded     int
-	SequencesAdded int
+	SchemasAdded     int
+	TablesAdded      int
+	ColumnsAdded     int
+	ConstraintsAdded int
+	IndexesAdded     int
+	RelationsAdded   int
+	DomainsAdded     int
+	EnumsAdded       int
+	ViewsAdded       int
+	SequencesAdded   int
 }
 
 // MergeOptions contains options for merge operations
@@ -120,8 +122,10 @@ func (r *MergeResult) mergeTables(schema *models.Schema, source *models.Schema,
 		}
 
 		if tgtTable, exists := existingTables[tableName]; exists {
-			// Table exists, merge its columns
+			// Table exists, merge its columns, constraints, and indexes
 			r.mergeColumns(tgtTable, srcTable)
+			r.mergeConstraints(tgtTable, srcTable)
+			r.mergeIndexes(tgtTable, srcTable)
 		} else {
 			// Table doesn't exist, add it
 			newTable := cloneTable(srcTable)
@@ -151,6 +155,52 @@ func (r *MergeResult) mergeColumns(table *models.Table, srcTable *models.Table)
 	}
 }
 
+func (r *MergeResult) mergeConstraints(table *models.Table, srcTable *models.Table) {
+	// Initialize constraints map if nil
+	if table.Constraints == nil {
+		table.Constraints = make(map[string]*models.Constraint)
+	}
+
+	// Create map of existing constraints
+	existingConstraints := make(map[string]*models.Constraint)
+	for constName := range table.Constraints {
+		existingConstraints[constName] = table.Constraints[constName]
+	}
+
+	// Merge constraints
+	for constName, srcConst := range srcTable.Constraints {
+		if _, exists := existingConstraints[constName]; !exists {
+			// Constraint doesn't exist, add it
+			newConst := cloneConstraint(srcConst)
+			table.Constraints[constName] = newConst
+			r.ConstraintsAdded++
+		}
+	}
+}
+
+func (r *MergeResult) mergeIndexes(table *models.Table, srcTable *models.Table) {
+	// Initialize indexes map if nil
+	if table.Indexes == nil {
+		table.Indexes = make(map[string]*models.Index)
+	}
+
+	// Create map of existing indexes
+	existingIndexes := make(map[string]*models.Index)
+	for idxName := range table.Indexes {
+		existingIndexes[idxName] = table.Indexes[idxName]
+	}
+
+	// Merge indexes
+	for idxName, srcIdx := range srcTable.Indexes {
+		if _, exists := existingIndexes[idxName]; !exists {
+			// Index doesn't exist, add it
+			newIdx := cloneIndex(srcIdx)
+			table.Indexes[idxName] = newIdx
+			r.IndexesAdded++
+		}
+	}
+}
+
 func (r *MergeResult) mergeViews(schema *models.Schema, source *models.Schema) {
 	// Create map of existing views
 	existingViews := make(map[string]*models.View)
@@ -552,6 +602,8 @@ func GetMergeSummary(result *MergeResult) string {
 		fmt.Sprintf("Schemas added:     %d", result.SchemasAdded),
 		fmt.Sprintf("Tables added:      %d", result.TablesAdded),
 		fmt.Sprintf("Columns added:     %d", result.ColumnsAdded),
+		fmt.Sprintf("Constraints added: %d", result.ConstraintsAdded),
+		fmt.Sprintf("Indexes added:     %d", result.IndexesAdded),
 		fmt.Sprintf("Views added:       %d", result.ViewsAdded),
 		fmt.Sprintf("Sequences added:   %d", result.SequencesAdded),
 		fmt.Sprintf("Enums added:       %d", result.EnumsAdded),
@@ -560,6 +612,7 @@ func GetMergeSummary(result *MergeResult) string {
 	}
 
 	totalAdded := result.SchemasAdded + result.TablesAdded + result.ColumnsAdded +
+		result.ConstraintsAdded + result.IndexesAdded +
 		result.ViewsAdded + result.SequencesAdded + result.EnumsAdded +
 		result.RelationsAdded + result.DomainsAdded
 

pkg/merge/merge_test.go

@@ -0,0 +1,617 @@
+package merge
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestMergeDatabases_NilInputs(t *testing.T) {
+	result := MergeDatabases(nil, nil, nil)
+	if result == nil {
+		t.Fatal("Expected non-nil result")
+	}
+	if result.SchemasAdded != 0 {
+		t.Errorf("Expected 0 schemas added, got %d", result.SchemasAdded)
+	}
+}
+
+func TestMergeDatabases_NewSchema(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "public"},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "auth"},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.SchemasAdded != 1 {
+		t.Errorf("Expected 1 schema added, got %d", result.SchemasAdded)
+	}
+	if len(target.Schemas) != 2 {
+		t.Errorf("Expected 2 schemas in target, got %d", len(target.Schemas))
+	}
+}
+
+func TestMergeDatabases_ExistingSchema(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "public"},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "public"},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.SchemasAdded != 0 {
+		t.Errorf("Expected 0 schemas added, got %d", result.SchemasAdded)
+	}
+	if len(target.Schemas) != 1 {
+		t.Errorf("Expected 1 schema in target, got %d", len(target.Schemas))
+	}
+}
+
+func TestMergeTables_NewTable(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "posts",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.TablesAdded != 1 {
+		t.Errorf("Expected 1 table added, got %d", result.TablesAdded)
+	}
+	if len(target.Schemas[0].Tables) != 2 {
+		t.Errorf("Expected 2 tables in target schema, got %d", len(target.Schemas[0].Tables))
+	}
+}
+
+func TestMergeColumns_NewColumn(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "int"},
+						},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"email": {Name: "email", Type: "varchar"},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ColumnsAdded != 1 {
+		t.Errorf("Expected 1 column added, got %d", result.ColumnsAdded)
+	}
+	if len(target.Schemas[0].Tables[0].Columns) != 2 {
+		t.Errorf("Expected 2 columns in target table, got %d", len(target.Schemas[0].Tables[0].Columns))
+	}
+}
+
+func TestMergeConstraints_NewConstraint(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:        "users",
+						Schema:      "public",
+						Columns:     map[string]*models.Column{},
+						Constraints: map[string]*models.Constraint{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Constraints: map[string]*models.Constraint{
+							"ukey_users_email": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"email"},
+								Name:    "ukey_users_email",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ConstraintsAdded != 1 {
+		t.Errorf("Expected 1 constraint added, got %d", result.ConstraintsAdded)
+	}
+	if len(target.Schemas[0].Tables[0].Constraints) != 1 {
+		t.Errorf("Expected 1 constraint in target table, got %d", len(target.Schemas[0].Tables[0].Constraints))
+	}
+}
+
+func TestMergeConstraints_NilConstraintsMap(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:        "users",
+						Schema:      "public",
+						Columns:     map[string]*models.Column{},
+						Constraints: nil, // Nil map
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Constraints: map[string]*models.Constraint{
+							"ukey_users_email": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"email"},
+								Name:    "ukey_users_email",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ConstraintsAdded != 1 {
+		t.Errorf("Expected 1 constraint added, got %d", result.ConstraintsAdded)
+	}
+	if target.Schemas[0].Tables[0].Constraints == nil {
+		t.Error("Expected constraints map to be initialized")
+	}
+	if len(target.Schemas[0].Tables[0].Constraints) != 1 {
+		t.Errorf("Expected 1 constraint in target table, got %d", len(target.Schemas[0].Tables[0].Constraints))
+	}
+}
+
+func TestMergeIndexes_NewIndex(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: map[string]*models.Index{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: map[string]*models.Index{
+							"idx_users_email": {
+								Name:    "idx_users_email",
+								Columns: []string{"email"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.IndexesAdded != 1 {
+		t.Errorf("Expected 1 index added, got %d", result.IndexesAdded)
+	}
+	if len(target.Schemas[0].Tables[0].Indexes) != 1 {
+		t.Errorf("Expected 1 index in target table, got %d", len(target.Schemas[0].Tables[0].Indexes))
+	}
+}
+
+func TestMergeIndexes_NilIndexesMap(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: nil, // Nil map
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: map[string]*models.Index{
+							"idx_users_email": {
+								Name:    "idx_users_email",
+								Columns: []string{"email"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.IndexesAdded != 1 {
+		t.Errorf("Expected 1 index added, got %d", result.IndexesAdded)
+	}
+	if target.Schemas[0].Tables[0].Indexes == nil {
+		t.Error("Expected indexes map to be initialized")
+	}
+	if len(target.Schemas[0].Tables[0].Indexes) != 1 {
+		t.Errorf("Expected 1 index in target table, got %d", len(target.Schemas[0].Tables[0].Indexes))
+	}
+}
+
+func TestMergeOptions_SkipTableNames(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "migrations",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+
+	opts := &MergeOptions{
+		SkipTableNames: map[string]bool{
+			"migrations": true,
+		},
+	}
+
+	result := MergeDatabases(target, source, opts)
+	if result.TablesAdded != 0 {
+		t.Errorf("Expected 0 tables added (skipped), got %d", result.TablesAdded)
+	}
+	if len(target.Schemas[0].Tables) != 1 {
+		t.Errorf("Expected 1 table in target schema, got %d", len(target.Schemas[0].Tables))
+	}
+}
+
+func TestMergeViews_NewView(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name:  "public",
+				Views: []*models.View{},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Views: []*models.View{
+					{
+						Name:       "user_summary",
+						Schema:     "public",
+						Definition: "SELECT * FROM users",
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ViewsAdded != 1 {
+		t.Errorf("Expected 1 view added, got %d", result.ViewsAdded)
+	}
+	if len(target.Schemas[0].Views) != 1 {
+		t.Errorf("Expected 1 view in target schema, got %d", len(target.Schemas[0].Views))
+	}
+}
+
+func TestMergeEnums_NewEnum(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name:  "public",
+				Enums: []*models.Enum{},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Enums: []*models.Enum{
+					{
+						Name:   "user_role",
+						Schema: "public",
+						Values: []string{"admin", "user"},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.EnumsAdded != 1 {
+		t.Errorf("Expected 1 enum added, got %d", result.EnumsAdded)
+	}
+	if len(target.Schemas[0].Enums) != 1 {
+		t.Errorf("Expected 1 enum in target schema, got %d", len(target.Schemas[0].Enums))
+	}
+}
+
+func TestMergeDomains_NewDomain(t *testing.T) {
+	target := &models.Database{
+		Domains: []*models.Domain{},
+	}
+	source := &models.Database{
+		Domains: []*models.Domain{
+			{
+				Name:        "auth",
+				Description: "Authentication domain",
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.DomainsAdded != 1 {
+		t.Errorf("Expected 1 domain added, got %d", result.DomainsAdded)
+	}
+	if len(target.Domains) != 1 {
+		t.Errorf("Expected 1 domain in target, got %d", len(target.Domains))
+	}
+}
+
+func TestMergeRelations_NewRelation(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name:      "public",
+				Relations: []*models.Relationship{},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Relations: []*models.Relationship{
+					{
+						Name:        "fk_posts_user",
+						Type:        models.OneToMany,
+						FromTable:   "posts",
+						FromColumns: []string{"user_id"},
+						ToTable:     "users",
+						ToColumns:   []string{"id"},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.RelationsAdded != 1 {
+		t.Errorf("Expected 1 relation added, got %d", result.RelationsAdded)
+	}
+	if len(target.Schemas[0].Relations) != 1 {
+		t.Errorf("Expected 1 relation in target schema, got %d", len(target.Schemas[0].Relations))
+	}
+}
+
+func TestGetMergeSummary(t *testing.T) {
+	result := &MergeResult{
+		SchemasAdded:     1,
+		TablesAdded:      2,
+		ColumnsAdded:     5,
+		ConstraintsAdded: 3,
+		IndexesAdded:     2,
+		ViewsAdded:       1,
+	}
+
+	summary := GetMergeSummary(result)
+	if summary == "" {
+		t.Error("Expected non-empty summary")
+	}
+	if len(summary) < 50 {
+		t.Errorf("Summary seems too short: %s", summary)
+	}
+}
+
+func TestGetMergeSummary_Nil(t *testing.T) {
+	summary := GetMergeSummary(nil)
+	if summary == "" {
+		t.Error("Expected non-empty summary for nil result")
+	}
+}
+
+func TestComplexMerge(t *testing.T) {
+	// Target with existing structure
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "int"},
+						},
+						Constraints: map[string]*models.Constraint{},
+						Indexes:     map[string]*models.Index{},
+					},
+				},
+			},
+		},
+	}
+
+	// Source with new columns, constraints, and indexes
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"email": {Name: "email", Type: "varchar"},
+							"guid":  {Name: "guid", Type: "uuid"},
+						},
+						Constraints: map[string]*models.Constraint{
+							"ukey_users_email": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"email"},
+								Name:    "ukey_users_email",
+							},
+							"ukey_users_guid": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"guid"},
+								Name:    "ukey_users_guid",
+							},
+						},
+						Indexes: map[string]*models.Index{
+							"idx_users_email": {
+								Name:    "idx_users_email",
+								Columns: []string{"email"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+
+	// Verify counts
+	if result.ColumnsAdded != 2 {
+		t.Errorf("Expected 2 columns added, got %d", result.ColumnsAdded)
+	}
+	if result.ConstraintsAdded != 2 {
+		t.Errorf("Expected 2 constraints added, got %d", result.ConstraintsAdded)
+	}
+	if result.IndexesAdded != 1 {
+		t.Errorf("Expected 1 index added, got %d", result.IndexesAdded)
+	}
+
+	// Verify target has merged data
+	table := target.Schemas[0].Tables[0]
+	if len(table.Columns) != 3 {
+		t.Errorf("Expected 3 columns in merged table, got %d", len(table.Columns))
+	}
+	if len(table.Constraints) != 2 {
+		t.Errorf("Expected 2 constraints in merged table, got %d", len(table.Constraints))
+	}
+	if len(table.Indexes) != 1 {
+		t.Errorf("Expected 1 index in merged table, got %d", len(table.Indexes))
+	}
+
+	// Verify specific constraint
+	if _, exists := table.Constraints["ukey_users_guid"]; !exists {
+		t.Error("Expected ukey_users_guid constraint to exist")
+	}
+}

pkg/pgsql/datatypes_test.go

@@ -0,0 +1,339 @@
+package pgsql
+
+import (
+	"testing"
+)
+
+func TestValidSQLType(t *testing.T) {
+	tests := []struct {
+		name    string
+		sqltype string
+		want    bool
+	}{
+		// PostgreSQL types
+		{"Valid PGSQL bigint", "bigint", true},
+		{"Valid PGSQL integer", "integer", true},
+		{"Valid PGSQL text", "text", true},
+		{"Valid PGSQL boolean", "boolean", true},
+		{"Valid PGSQL double precision", "double precision", true},
+		{"Valid PGSQL bytea", "bytea", true},
+		{"Valid PGSQL uuid", "uuid", true},
+		{"Valid PGSQL jsonb", "jsonb", true},
+		{"Valid PGSQL json", "json", true},
+		{"Valid PGSQL timestamp", "timestamp", true},
+		{"Valid PGSQL date", "date", true},
+		{"Valid PGSQL time", "time", true},
+		{"Valid PGSQL citext", "citext", true},
+
+		// Standard types
+		{"Valid std double", "double", true},
+		{"Valid std blob", "blob", true},
+
+		// Case insensitive
+		{"Case insensitive BIGINT", "BIGINT", true},
+		{"Case insensitive TeXt", "TeXt", true},
+		{"Case insensitive BoOlEaN", "BoOlEaN", true},
+
+		// Invalid types
+		{"Invalid type", "invalidtype", false},
+		{"Invalid type varchar", "varchar", false},
+		{"Empty string", "", false},
+		{"Random string", "foobar", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ValidSQLType(tt.sqltype)
+			if got != tt.want {
+				t.Errorf("ValidSQLType(%q) = %v, want %v", tt.sqltype, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetSQLType(t *testing.T) {
+	tests := []struct {
+		name    string
+		anytype string
+		want    string
+	}{
+		// Go types to PostgreSQL types
+		{"Go bool to boolean", "bool", "boolean"},
+		{"Go int64 to bigint", "int64", "bigint"},
+		{"Go int to integer", "int", "integer"},
+		{"Go string to text", "string", "text"},
+		{"Go float64 to double precision", "float64", "double precision"},
+		{"Go float32 to real", "float32", "real"},
+		{"Go []byte to bytea", "[]byte", "bytea"},
+
+		// SQL types remain SQL types
+		{"SQL bigint", "bigint", "bigint"},
+		{"SQL integer", "integer", "integer"},
+		{"SQL text", "text", "text"},
+		{"SQL boolean", "boolean", "boolean"},
+		{"SQL uuid", "uuid", "uuid"},
+		{"SQL jsonb", "jsonb", "jsonb"},
+
+		// Case insensitive Go types
+		{"Case insensitive BOOL", "BOOL", "boolean"},
+		{"Case insensitive InT64", "InT64", "bigint"},
+		{"Case insensitive STRING", "STRING", "text"},
+
+		// Case insensitive SQL types
+		{"Case insensitive BIGINT", "BIGINT", "bigint"},
+		{"Case insensitive TEXT", "TEXT", "text"},
+
+		// Custom types
+		{"Custom sqluuid", "sqluuid", "uuid"},
+		{"Custom sqljsonb", "sqljsonb", "jsonb"},
+		{"Custom sqlint64", "sqlint64", "bigint"},
+
+		// Unknown types default to text
+		{"Unknown type varchar", "varchar", "text"},
+		{"Unknown type foobar", "foobar", "text"},
+		{"Empty string", "", "text"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetSQLType(tt.anytype)
+			if got != tt.want {
+				t.Errorf("GetSQLType(%q) = %q, want %q", tt.anytype, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestConvertSQLType(t *testing.T) {
+	tests := []struct {
+		name    string
+		anytype string
+		want    string
+	}{
+		// Go types to PostgreSQL types
+		{"Go bool to boolean", "bool", "boolean"},
+		{"Go int64 to bigint", "int64", "bigint"},
+		{"Go int to integer", "int", "integer"},
+		{"Go string to text", "string", "text"},
+		{"Go float64 to double precision", "float64", "double precision"},
+		{"Go float32 to real", "float32", "real"},
+		{"Go []byte to bytea", "[]byte", "bytea"},
+
+		// SQL types remain SQL types
+		{"SQL bigint", "bigint", "bigint"},
+		{"SQL integer", "integer", "integer"},
+		{"SQL text", "text", "text"},
+		{"SQL boolean", "boolean", "boolean"},
+
+		// Case insensitive
+		{"Case insensitive BOOL", "BOOL", "boolean"},
+		{"Case insensitive InT64", "InT64", "bigint"},
+
+		// Unknown types remain unchanged (difference from GetSQLType)
+		{"Unknown type varchar", "varchar", "varchar"},
+		{"Unknown type foobar", "foobar", "foobar"},
+		{"Empty string", "", ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ConvertSQLType(tt.anytype)
+			if got != tt.want {
+				t.Errorf("ConvertSQLType(%q) = %q, want %q", tt.anytype, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsGoType(t *testing.T) {
+	tests := []struct {
+		name     string
+		typeName string
+		want     bool
+	}{
+		// Go basic types
+		{"Go bool", "bool", true},
+		{"Go int64", "int64", true},
+		{"Go int", "int", true},
+		{"Go int32", "int32", true},
+		{"Go int16", "int16", true},
+		{"Go int8", "int8", true},
+		{"Go uint", "uint", true},
+		{"Go uint64", "uint64", true},
+		{"Go uint32", "uint32", true},
+		{"Go uint16", "uint16", true},
+		{"Go uint8", "uint8", true},
+		{"Go float64", "float64", true},
+		{"Go float32", "float32", true},
+		{"Go string", "string", true},
+		{"Go []byte", "[]byte", true},
+
+		// Go custom types
+		{"Go complex64", "complex64", true},
+		{"Go complex128", "complex128", true},
+		{"Go uintptr", "uintptr", true},
+		{"Go Pointer", "Pointer", true},
+
+		// Custom SQL types
+		{"Custom sqluuid", "sqluuid", true},
+		{"Custom sqljsonb", "sqljsonb", true},
+		{"Custom sqlint64", "sqlint64", true},
+		{"Custom customdate", "customdate", true},
+		{"Custom customtime", "customtime", true},
+
+		// Case insensitive
+		{"Case insensitive BOOL", "BOOL", true},
+		{"Case insensitive InT64", "InT64", true},
+		{"Case insensitive STRING", "STRING", true},
+
+		// SQL types (not Go types)
+		{"SQL bigint", "bigint", false},
+		{"SQL integer", "integer", false},
+		{"SQL text", "text", false},
+		{"SQL boolean", "boolean", false},
+
+		// Invalid types
+		{"Invalid type", "invalidtype", false},
+		{"Empty string", "", false},
+		{"Random string", "foobar", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := IsGoType(tt.typeName)
+			if got != tt.want {
+				t.Errorf("IsGoType(%q) = %v, want %v", tt.typeName, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetStdTypeFromGo(t *testing.T) {
+	tests := []struct {
+		name     string
+		typeName string
+		want     string
+	}{
+		// Go types to standard SQL types
+		{"Go bool to boolean", "bool", "boolean"},
+		{"Go int64 to bigint", "int64", "bigint"},
+		{"Go int to integer", "int", "integer"},
+		{"Go string to text", "string", "text"},
+		{"Go float64 to double", "float64", "double"},
+		{"Go float32 to double", "float32", "double"},
+		{"Go []byte to blob", "[]byte", "blob"},
+		{"Go int32 to integer", "int32", "integer"},
+		{"Go int16 to smallint", "int16", "smallint"},
+
+		// Custom types
+		{"Custom sqluuid to uuid", "sqluuid", "uuid"},
+		{"Custom sqljsonb to jsonb", "sqljsonb", "jsonb"},
+		{"Custom sqlint64 to bigint", "sqlint64", "bigint"},
+		{"Custom customdate to date", "customdate", "date"},
+
+		// Case insensitive
+		{"Case insensitive BOOL", "BOOL", "boolean"},
+		{"Case insensitive InT64", "InT64", "bigint"},
+		{"Case insensitive STRING", "STRING", "text"},
+
+		// Non-Go types remain unchanged
+		{"SQL bigint unchanged", "bigint", "bigint"},
+		{"SQL integer unchanged", "integer", "integer"},
+		{"Invalid type unchanged", "invalidtype", "invalidtype"},
+		{"Empty string unchanged", "", ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetStdTypeFromGo(tt.typeName)
+			if got != tt.want {
+				t.Errorf("GetStdTypeFromGo(%q) = %q, want %q", tt.typeName, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGoToStdTypesMap(t *testing.T) {
+	// Test that the map contains expected entries
+	expectedMappings := map[string]string{
+		"bool":    "boolean",
+		"int64":   "bigint",
+		"int":     "integer",
+		"string":  "text",
+		"float64": "double",
+		"[]byte":  "blob",
+	}
+
+	for goType, expectedStd := range expectedMappings {
+		if stdType, ok := GoToStdTypes[goType]; !ok {
+			t.Errorf("GoToStdTypes missing entry for %q", goType)
+		} else if stdType != expectedStd {
+			t.Errorf("GoToStdTypes[%q] = %q, want %q", goType, stdType, expectedStd)
+		}
+	}
+
+	// Test that the map is not empty
+	if len(GoToStdTypes) == 0 {
+		t.Error("GoToStdTypes map is empty")
+	}
+}
+
+func TestGoToPGSQLTypesMap(t *testing.T) {
+	// Test that the map contains expected entries
+	expectedMappings := map[string]string{
+		"bool":    "boolean",
+		"int64":   "bigint",
+		"int":     "integer",
+		"string":  "text",
+		"float64": "double precision",
+		"float32": "real",
+		"[]byte":  "bytea",
+	}
+
+	for goType, expectedPG := range expectedMappings {
+		if pgType, ok := GoToPGSQLTypes[goType]; !ok {
+			t.Errorf("GoToPGSQLTypes missing entry for %q", goType)
+		} else if pgType != expectedPG {
+			t.Errorf("GoToPGSQLTypes[%q] = %q, want %q", goType, pgType, expectedPG)
+		}
+	}
+
+	// Test that the map is not empty
+	if len(GoToPGSQLTypes) == 0 {
+		t.Error("GoToPGSQLTypes map is empty")
+	}
+}
+
+func TestTypeConversionConsistency(t *testing.T) {
+	// Test that GetSQLType and ConvertSQLType are consistent for known types
+	knownGoTypes := []string{"bool", "int64", "int", "string", "float64", "[]byte"}
+
+	for _, goType := range knownGoTypes {
+		getSQLResult := GetSQLType(goType)
+		convertResult := ConvertSQLType(goType)
+
+		if getSQLResult != convertResult {
+			t.Errorf("Inconsistent results for %q: GetSQLType=%q, ConvertSQLType=%q",
+				goType, getSQLResult, convertResult)
+		}
+	}
+}
+
+func TestGetSQLTypeVsConvertSQLTypeDifference(t *testing.T) {
+	// Test that GetSQLType returns "text" for unknown types
+	// while ConvertSQLType returns the input unchanged
+	unknownTypes := []string{"varchar", "char", "customtype", "unknowntype"}
+
+	for _, unknown := range unknownTypes {
+		getSQLResult := GetSQLType(unknown)
+		convertResult := ConvertSQLType(unknown)
+
+		if getSQLResult != "text" {
+			t.Errorf("GetSQLType(%q) = %q, want %q", unknown, getSQLResult, "text")
+		}
+
+		if convertResult != unknown {
+			t.Errorf("ConvertSQLType(%q) = %q, want %q", unknown, convertResult, unknown)
+		}
+	}
+}

pkg/pgsql/keywords_test.go

@@ -0,0 +1,136 @@
+package pgsql
+
+import (
+	"testing"
+)
+
+func TestGetPostgresKeywords(t *testing.T) {
+	keywords := GetPostgresKeywords()
+
+	// Test that keywords are returned
+	if len(keywords) == 0 {
+		t.Fatal("Expected non-empty list of keywords")
+	}
+
+	// Test that we get all keywords from the map
+	expectedCount := len(postgresKeywords)
+	if len(keywords) != expectedCount {
+		t.Errorf("Expected %d keywords, got %d", expectedCount, len(keywords))
+	}
+
+	// Test that all returned keywords exist in the map
+	for _, keyword := range keywords {
+		if !postgresKeywords[keyword] {
+			t.Errorf("Keyword %q not found in postgresKeywords map", keyword)
+		}
+	}
+
+	// Test that no duplicate keywords are returned
+	seen := make(map[string]bool)
+	for _, keyword := range keywords {
+		if seen[keyword] {
+			t.Errorf("Duplicate keyword found: %q", keyword)
+		}
+		seen[keyword] = true
+	}
+}
+
+func TestPostgresKeywordsMap(t *testing.T) {
+	tests := []struct {
+		name    string
+		keyword string
+		want    bool
+	}{
+		{"SELECT keyword", "select", true},
+		{"FROM keyword", "from", true},
+		{"WHERE keyword", "where", true},
+		{"TABLE keyword", "table", true},
+		{"PRIMARY keyword", "primary", true},
+		{"FOREIGN keyword", "foreign", true},
+		{"CREATE keyword", "create", true},
+		{"DROP keyword", "drop", true},
+		{"ALTER keyword", "alter", true},
+		{"INDEX keyword", "index", true},
+		{"NOT keyword", "not", true},
+		{"NULL keyword", "null", true},
+		{"TRUE keyword", "true", true},
+		{"FALSE keyword", "false", true},
+		{"Non-keyword lowercase", "notakeyword", false},
+		{"Non-keyword uppercase", "NOTAKEYWORD", false},
+		{"Empty string", "", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := postgresKeywords[tt.keyword]
+			if got != tt.want {
+				t.Errorf("postgresKeywords[%q] = %v, want %v", tt.keyword, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestPostgresKeywordsMapContent(t *testing.T) {
+	// Test that the map contains expected common keywords
+	commonKeywords := []string{
+		"select", "insert", "update", "delete", "create", "drop", "alter",
+		"table", "index", "view", "schema", "function", "procedure",
+		"primary", "foreign", "key", "constraint", "unique", "check",
+		"null", "not", "and", "or", "like", "in", "between",
+		"join", "inner", "left", "right", "cross", "full", "outer",
+		"where", "having", "group", "order", "limit", "offset",
+		"union", "intersect", "except",
+		"begin", "commit", "rollback", "transaction",
+	}
+
+	for _, keyword := range commonKeywords {
+		if !postgresKeywords[keyword] {
+			t.Errorf("Expected common keyword %q to be in postgresKeywords map", keyword)
+		}
+	}
+}
+
+func TestPostgresKeywordsMapSize(t *testing.T) {
+	// PostgreSQL has a substantial list of reserved keywords
+	// This test ensures the map has a reasonable number of entries
+	minExpectedKeywords := 200 // PostgreSQL 13+ has 400+ reserved words
+
+	if len(postgresKeywords) < minExpectedKeywords {
+		t.Errorf("Expected at least %d keywords, got %d. The map may be incomplete.",
+			minExpectedKeywords, len(postgresKeywords))
+	}
+}
+
+func TestGetPostgresKeywordsConsistency(t *testing.T) {
+	// Test that calling GetPostgresKeywords multiple times returns consistent results
+	keywords1 := GetPostgresKeywords()
+	keywords2 := GetPostgresKeywords()
+
+	if len(keywords1) != len(keywords2) {
+		t.Errorf("Inconsistent results: first call returned %d keywords, second call returned %d",
+			len(keywords1), len(keywords2))
+	}
+
+	// Create a map from both results to compare
+	map1 := make(map[string]bool)
+	map2 := make(map[string]bool)
+
+	for _, k := range keywords1 {
+		map1[k] = true
+	}
+	for _, k := range keywords2 {
+		map2[k] = true
+	}
+
+	// Check that both contain the same keywords
+	for k := range map1 {
+		if !map2[k] {
+			t.Errorf("Keyword %q present in first call but not in second", k)
+		}
+	}
+	for k := range map2 {
+		if !map1[k] {
+			t.Errorf("Keyword %q present in second call but not in first", k)
+		}
+	}
+}

pkg/readers/dbml/reader.go

@@ -603,8 +603,10 @@ func (r *Reader) parseColumn(line, tableName, schemaName string) (*models.Column
 					column.Default = strings.Trim(defaultVal, "'\"")
 				} else if attr == "unique" {
 					// Create a unique constraint
+					// Clean table name by removing leading underscores to avoid double underscores
+					cleanTableName := strings.TrimLeft(tableName, "_")
 					uniqueConstraint := models.InitConstraint(
-						fmt.Sprintf("uq_%s", columnName),
+						fmt.Sprintf("ukey_%s_%s", cleanTableName, columnName),
 						models.UniqueConstraint,
 					)
 					uniqueConstraint.Schema = schemaName
@@ -652,8 +654,8 @@ func (r *Reader) parseColumn(line, tableName, schemaName string) (*models.Column
 							constraint.Table = tableName
 							constraint.Columns = []string{columnName}
 						}
-						// Generate short constraint name based on the column
-						constraint.Name = fmt.Sprintf("fk_%s", constraint.Columns[0])
+						// Generate constraint name based on table and columns
+						constraint.Name = fmt.Sprintf("fk_%s_%s", constraint.Table, strings.Join(constraint.Columns, "_"))
 					}
 				}
 			}
@@ -737,7 +739,11 @@ func (r *Reader) parseIndex(line, tableName, schemaName string) *models.Index {
 
 	// Generate name if not provided
 	if index.Name == "" {
-		index.Name = fmt.Sprintf("idx_%s_%s", tableName, strings.Join(columns, "_"))
+		prefix := "idx"
+		if index.Unique {
+			prefix = "uidx"
+		}
+		index.Name = fmt.Sprintf("%s_%s_%s", prefix, tableName, strings.Join(columns, "_"))
 	}
 
 	return index
@@ -797,10 +803,10 @@ func (r *Reader) parseRef(refStr string) *models.Constraint {
 		return nil
 	}
 
-	// Generate short constraint name based on the source column
-	constraintName := fmt.Sprintf("fk_%s_%s", fromTable, toTable)
-	if len(fromColumns) > 0 {
-		constraintName = fmt.Sprintf("fk_%s", fromColumns[0])
+	// Generate constraint name based on table and columns
+	constraintName := fmt.Sprintf("fk_%s_%s", fromTable, strings.Join(fromColumns, "_"))
+	if len(fromColumns) == 0 {
+		constraintName = fmt.Sprintf("fk_%s_%s", fromTable, toTable)
 	}
 
 	constraint := models.InitConstraint(

pkg/readers/dbml/reader_test.go

@@ -777,6 +777,76 @@ func TestParseFilePrefix(t *testing.T) {
 	}
 }
 
+func TestConstraintNaming(t *testing.T) {
+	// Test that constraints are named with proper prefixes
+	opts := &readers.ReaderOptions{
+		FilePath: filepath.Join("..", "..", "..", "tests", "assets", "dbml", "complex.dbml"),
+	}
+
+	reader := NewReader(opts)
+	db, err := reader.ReadDatabase()
+	if err != nil {
+		t.Fatalf("ReadDatabase() error = %v", err)
+	}
+
+	// Find users table
+	var usersTable *models.Table
+	var postsTable *models.Table
+	for _, schema := range db.Schemas {
+		for _, table := range schema.Tables {
+			if table.Name == "users" {
+				usersTable = table
+			} else if table.Name == "posts" {
+				postsTable = table
+			}
+		}
+	}
+
+	if usersTable == nil {
+		t.Fatal("Users table not found")
+	}
+	if postsTable == nil {
+		t.Fatal("Posts table not found")
+	}
+
+	// Test unique constraint naming: ukey_table_column
+	if _, exists := usersTable.Constraints["ukey_users_email"]; !exists {
+		t.Error("Expected unique constraint 'ukey_users_email' not found")
+		t.Logf("Available constraints: %v", getKeys(usersTable.Constraints))
+	}
+
+	if _, exists := postsTable.Constraints["ukey_posts_slug"]; !exists {
+		t.Error("Expected unique constraint 'ukey_posts_slug' not found")
+		t.Logf("Available constraints: %v", getKeys(postsTable.Constraints))
+	}
+
+	// Test foreign key naming: fk_table_column
+	if _, exists := postsTable.Constraints["fk_posts_user_id"]; !exists {
+		t.Error("Expected foreign key 'fk_posts_user_id' not found")
+		t.Logf("Available constraints: %v", getKeys(postsTable.Constraints))
+	}
+
+	// Test unique index naming: uidx_table_columns
+	if _, exists := postsTable.Indexes["uidx_posts_slug"]; !exists {
+		t.Error("Expected unique index 'uidx_posts_slug' not found")
+		t.Logf("Available indexes: %v", getKeys(postsTable.Indexes))
+	}
+
+	// Test regular index naming: idx_table_columns
+	if _, exists := postsTable.Indexes["idx_posts_user_id_published"]; !exists {
+		t.Error("Expected index 'idx_posts_user_id_published' not found")
+		t.Logf("Available indexes: %v", getKeys(postsTable.Indexes))
+	}
+}
+
+func getKeys[V any](m map[string]V) []string {
+	keys := make([]string, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+	return keys
+}
+
 func TestHasCommentedRefs(t *testing.T) {
 	// Test with the actual multifile test fixtures
 	tests := []struct {

pkg/reflectutil/helpers_test.go

@@ -0,0 +1,490 @@
+package reflectutil
+
+import (
+	"reflect"
+	"testing"
+)
+
+type testStruct struct {
+	Name    string
+	Age     int
+	Active  bool
+	Nested  *nestedStruct
+	Private string
+}
+
+type nestedStruct struct {
+	Value string
+	Count int
+}
+
+func TestDeref(t *testing.T) {
+	tests := []struct {
+		name      string
+		input     interface{}
+		wantValid bool
+		wantKind  reflect.Kind
+	}{
+		{
+			name:      "non-pointer int",
+			input:     42,
+			wantValid: true,
+			wantKind:  reflect.Int,
+		},
+		{
+			name:      "single pointer",
+			input:     ptrInt(42),
+			wantValid: true,
+			wantKind:  reflect.Int,
+		},
+		{
+			name:      "double pointer",
+			input:     ptrPtr(ptrInt(42)),
+			wantValid: true,
+			wantKind:  reflect.Int,
+		},
+		{
+			name:      "nil pointer",
+			input:     (*int)(nil),
+			wantValid: false,
+			wantKind:  reflect.Ptr,
+		},
+		{
+			name:      "string",
+			input:     "test",
+			wantValid: true,
+			wantKind:  reflect.String,
+		},
+		{
+			name:      "struct",
+			input:     testStruct{Name: "test"},
+			wantValid: true,
+			wantKind:  reflect.Struct,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			v := reflect.ValueOf(tt.input)
+			got, valid := Deref(v)
+
+			if valid != tt.wantValid {
+				t.Errorf("Deref() valid = %v, want %v", valid, tt.wantValid)
+			}
+
+			if got.Kind() != tt.wantKind {
+				t.Errorf("Deref() kind = %v, want %v", got.Kind(), tt.wantKind)
+			}
+		})
+	}
+}
+
+func TestDerefInterface(t *testing.T) {
+	i := 42
+	pi := &i
+	ppi := &pi
+
+	tests := []struct {
+		name     string
+		input    interface{}
+		wantKind reflect.Kind
+	}{
+		{"int", 42, reflect.Int},
+		{"pointer to int", &i, reflect.Int},
+		{"double pointer to int", ppi, reflect.Int},
+		{"string", "test", reflect.String},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DerefInterface(tt.input)
+			if got.Kind() != tt.wantKind {
+				t.Errorf("DerefInterface() kind = %v, want %v", got.Kind(), tt.wantKind)
+			}
+		})
+	}
+}
+
+func TestGetFieldValue(t *testing.T) {
+	ts := testStruct{
+		Name:   "John",
+		Age:    30,
+		Active: true,
+		Nested: &nestedStruct{Value: "nested", Count: 5},
+	}
+
+	tests := []struct {
+		name  string
+		item  interface{}
+		field string
+		want  interface{}
+	}{
+		{"struct field Name", ts, "Name", "John"},
+		{"struct field Age", ts, "Age", 30},
+		{"struct field Active", ts, "Active", true},
+		{"struct non-existent field", ts, "NonExistent", nil},
+		{"pointer to struct", &ts, "Name", "John"},
+		{"map string key", map[string]string{"key": "value"}, "key", "value"},
+		{"map int key", map[string]int{"count": 42}, "count", 42},
+		{"map non-existent key", map[string]string{"key": "value"}, "missing", nil},
+		{"nil pointer", (*testStruct)(nil), "Name", nil},
+		{"non-struct non-map", 42, "field", nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetFieldValue(tt.item, tt.field)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetFieldValue() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsSliceOrArray(t *testing.T) {
+	arr := [3]int{1, 2, 3}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		want  bool
+	}{
+		{"slice", []int{1, 2, 3}, true},
+		{"array", arr, true},
+		{"pointer to slice", &[]int{1, 2, 3}, true},
+		{"string", "test", false},
+		{"int", 42, false},
+		{"map", map[string]int{}, false},
+		{"nil slice", ([]int)(nil), true}, // nil slice is still Kind==Slice
+		{"nil pointer", (*[]int)(nil), false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := IsSliceOrArray(tt.input)
+			if got != tt.want {
+				t.Errorf("IsSliceOrArray() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsMap(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  bool
+	}{
+		{"map[string]int", map[string]int{"a": 1}, true},
+		{"map[int]string", map[int]string{1: "a"}, true},
+		{"pointer to map", &map[string]int{"a": 1}, true},
+		{"slice", []int{1, 2, 3}, false},
+		{"string", "test", false},
+		{"int", 42, false},
+		{"nil map", (map[string]int)(nil), true}, // nil map is still Kind==Map
+		{"nil pointer", (*map[string]int)(nil), false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := IsMap(tt.input)
+			if got != tt.want {
+				t.Errorf("IsMap() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSliceLen(t *testing.T) {
+	arr := [3]int{1, 2, 3}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		want  int
+	}{
+		{"slice length 3", []int{1, 2, 3}, 3},
+		{"empty slice", []int{}, 0},
+		{"array length 3", arr, 3},
+		{"pointer to slice", &[]int{1, 2, 3}, 3},
+		{"not a slice", "test", 0},
+		{"int", 42, 0},
+		{"nil slice", ([]int)(nil), 0},
+		{"nil pointer", (*[]int)(nil), 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SliceLen(tt.input)
+			if got != tt.want {
+				t.Errorf("SliceLen() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestMapLen(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  int
+	}{
+		{"map length 2", map[string]int{"a": 1, "b": 2}, 2},
+		{"empty map", map[string]int{}, 0},
+		{"pointer to map", &map[string]int{"a": 1}, 1},
+		{"not a map", []int{1, 2, 3}, 0},
+		{"string", "test", 0},
+		{"nil map", (map[string]int)(nil), 0},
+		{"nil pointer", (*map[string]int)(nil), 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapLen(tt.input)
+			if got != tt.want {
+				t.Errorf("MapLen() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSliceToInterfaces(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  []interface{}
+	}{
+		{"int slice", []int{1, 2, 3}, []interface{}{1, 2, 3}},
+		{"string slice", []string{"a", "b"}, []interface{}{"a", "b"}},
+		{"empty slice", []int{}, []interface{}{}},
+		{"pointer to slice", &[]int{1, 2}, []interface{}{1, 2}},
+		{"not a slice", "test", []interface{}{}},
+		{"nil slice", ([]int)(nil), []interface{}{}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SliceToInterfaces(tt.input)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("SliceToInterfaces() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestMapKeys(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  []interface{}
+	}{
+		{"map with keys", map[string]int{"a": 1, "b": 2}, []interface{}{"a", "b"}},
+		{"empty map", map[string]int{}, []interface{}{}},
+		{"not a map", []int{1, 2, 3}, []interface{}{}},
+		{"nil map", (map[string]int)(nil), []interface{}{}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapKeys(tt.input)
+			if len(got) != len(tt.want) {
+				t.Errorf("MapKeys() length = %v, want %v", len(got), len(tt.want))
+			}
+			// For maps, order is not guaranteed, so just check length
+		})
+	}
+}
+
+func TestMapValues(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  int // length of values
+	}{
+		{"map with values", map[string]int{"a": 1, "b": 2}, 2},
+		{"empty map", map[string]int{}, 0},
+		{"not a map", []int{1, 2, 3}, 0},
+		{"nil map", (map[string]int)(nil), 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapValues(tt.input)
+			if len(got) != tt.want {
+				t.Errorf("MapValues() length = %v, want %v", len(got), tt.want)
+			}
+		})
+	}
+}
+
+func TestMapGet(t *testing.T) {
+	m := map[string]int{"a": 1, "b": 2}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		key   interface{}
+		want  interface{}
+	}{
+		{"existing key", m, "a", 1},
+		{"existing key b", m, "b", 2},
+		{"non-existing key", m, "c", nil},
+		{"pointer to map", &m, "a", 1},
+		{"not a map", []int{1, 2}, 0, nil},
+		{"nil map", (map[string]int)(nil), "a", nil},
+		{"nil pointer", (*map[string]int)(nil), "a", nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapGet(tt.input, tt.key)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("MapGet() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSliceIndex(t *testing.T) {
+	s := []int{10, 20, 30}
+
+	tests := []struct {
+		name  string
+		slice interface{}
+		index int
+		want  interface{}
+	}{
+		{"index 0", s, 0, 10},
+		{"index 1", s, 1, 20},
+		{"index 2", s, 2, 30},
+		{"negative index", s, -1, nil},
+		{"out of bounds", s, 5, nil},
+		{"pointer to slice", &s, 1, 20},
+		{"not a slice", "test", 0, nil},
+		{"nil slice", ([]int)(nil), 0, nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SliceIndex(tt.slice, tt.index)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("SliceIndex() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestCompareValues(t *testing.T) {
+	tests := []struct {
+		name string
+		a    interface{}
+		b    interface{}
+		want int
+	}{
+		{"both nil", nil, nil, 0},
+		{"a nil", nil, 5, -1},
+		{"b nil", 5, nil, 1},
+		{"equal strings", "abc", "abc", 0},
+		{"a less than b strings", "abc", "xyz", -1},
+		{"a greater than b strings", "xyz", "abc", 1},
+		{"equal ints", 5, 5, 0},
+		{"a less than b ints", 3, 7, -1},
+		{"a greater than b ints", 10, 5, 1},
+		{"equal floats", 3.14, 3.14, 0},
+		{"a less than b floats", 2.5, 5.5, -1},
+		{"a greater than b floats", 10.5, 5.5, 1},
+		{"equal uints", uint(5), uint(5), 0},
+		{"different types", "abc", 123, 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := CompareValues(tt.a, tt.b)
+			if got != tt.want {
+				t.Errorf("CompareValues(%v, %v) = %v, want %v", tt.a, tt.b, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetNestedValue(t *testing.T) {
+	nested := map[string]interface{}{
+		"level1": map[string]interface{}{
+			"level2": map[string]interface{}{
+				"value": "deep",
+			},
+		},
+	}
+
+	ts := testStruct{
+		Name: "John",
+		Nested: &nestedStruct{
+			Value: "nested value",
+			Count: 42,
+		},
+	}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		path  string
+		want  interface{}
+	}{
+		{"empty path", nested, "", nested},
+		{"single level map", nested, "level1", nested["level1"]},
+		{"nested map", nested, "level1.level2", map[string]interface{}{"value": "deep"}},
+		{"deep nested map", nested, "level1.level2.value", "deep"},
+		{"struct field", ts, "Name", "John"},
+		{"nested struct field", ts, "Nested", ts.Nested},
+		{"non-existent path", nested, "missing.path", nil},
+		{"nil input", nil, "path", nil},
+		{"partial missing path", nested, "level1.missing", nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetNestedValue(tt.input, tt.path)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetNestedValue() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDeepEqual(t *testing.T) {
+	tests := []struct {
+		name string
+		a    interface{}
+		b    interface{}
+		want bool
+	}{
+		{"equal ints", 42, 42, true},
+		{"different ints", 42, 43, false},
+		{"equal strings", "test", "test", true},
+		{"different strings", "test", "other", false},
+		{"equal slices", []int{1, 2, 3}, []int{1, 2, 3}, true},
+		{"different slices", []int{1, 2, 3}, []int{1, 2, 4}, false},
+		{"equal maps", map[string]int{"a": 1}, map[string]int{"a": 1}, true},
+		{"different maps", map[string]int{"a": 1}, map[string]int{"a": 2}, false},
+		{"both nil", nil, nil, true},
+		{"one nil", nil, 42, false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DeepEqual(tt.a, tt.b)
+			if got != tt.want {
+				t.Errorf("DeepEqual(%v, %v) = %v, want %v", tt.a, tt.b, got, tt.want)
+			}
+		})
+	}
+}
+
+// Helper functions
+func ptrInt(i int) *int {
+	return &i
+}
+
+func ptrPtr(p *int) **int {
+	return &p
+}

pkg/writers/pgsql/migration_writer_test.go

@@ -215,3 +215,70 @@ func TestTemplateExecutor_AuditFunction(t *testing.T) {
 		t.Error("SQL missing DELETE handling")
 	}
 }
+
+func TestWriteMigration_NumericConstraintNames(t *testing.T) {
+	// Current database (empty)
+	current := models.InitDatabase("testdb")
+	currentSchema := models.InitSchema("entity")
+	current.Schemas = append(current.Schemas, currentSchema)
+
+	// Model database (with constraint starting with number)
+	model := models.InitDatabase("testdb")
+	modelSchema := models.InitSchema("entity")
+
+	// Create individual_actor_relationship table
+	table := models.InitTable("individual_actor_relationship", "entity")
+	idCol := models.InitColumn("id", "individual_actor_relationship", "entity")
+	idCol.Type = "integer"
+	idCol.IsPrimaryKey = true
+	table.Columns["id"] = idCol
+
+	actorIDCol := models.InitColumn("actor_id", "individual_actor_relationship", "entity")
+	actorIDCol.Type = "integer"
+	table.Columns["actor_id"] = actorIDCol
+
+	// Add constraint with name starting with number
+	constraint := &models.Constraint{
+		Name:              "215162_fk_actor",
+		Type:              models.ForeignKeyConstraint,
+		Columns:           []string{"actor_id"},
+		ReferencedSchema:  "entity",
+		ReferencedTable:   "actor",
+		ReferencedColumns: []string{"id"},
+		OnDelete:          "CASCADE",
+		OnUpdate:          "NO ACTION",
+	}
+	table.Constraints["215162_fk_actor"] = constraint
+
+	modelSchema.Tables = append(modelSchema.Tables, table)
+	model.Schemas = append(model.Schemas, modelSchema)
+
+	// Generate migration
+	var buf bytes.Buffer
+	writer, err := NewMigrationWriter(&writers.WriterOptions{})
+	if err != nil {
+		t.Fatalf("Failed to create writer: %v", err)
+	}
+	writer.writer = &buf
+
+	err = writer.WriteMigration(model, current)
+	if err != nil {
+		t.Fatalf("WriteMigration failed: %v", err)
+	}
+
+	output := buf.String()
+	t.Logf("Generated migration:\n%s", output)
+
+	// Verify constraint name is properly quoted
+	if !strings.Contains(output, `"215162_fk_actor"`) {
+		t.Error("Constraint name starting with number should be quoted")
+	}
+
+	// Verify the SQL is syntactically correct (contains required keywords)
+	if !strings.Contains(output, "ADD CONSTRAINT") {
+		t.Error("Migration missing ADD CONSTRAINT")
+	}
+	if !strings.Contains(output, "FOREIGN KEY") {
+		t.Error("Migration missing FOREIGN KEY")
+	}
+}

pkg/writers/pgsql/template_functions.go

@@ -21,6 +21,7 @@ func TemplateFunctions() map[string]interface{} {
 		"quote":           quote,
 		"escape":          escape,
 		"safe_identifier": safeIdentifier,
+		"quote_ident":     quoteIdent,
 
 		// Type conversion
 		"goTypeToSQL": goTypeToSQL,
@@ -122,6 +123,43 @@ func safeIdentifier(s string) string {
 	return strings.ToLower(safe)
 }
 
+// quoteIdent quotes a PostgreSQL identifier if necessary
+// Identifiers need quoting if they:
+// - Start with a digit
+// - Contain special characters
+// - Are reserved keywords
+// - Contain uppercase letters (to preserve case)
+func quoteIdent(s string) string {
+	if s == "" {
+		return `""`
+	}
+
+	// Check if quoting is needed
+	needsQuoting := unicode.IsDigit(rune(s[0]))
+
+	// Starts with digit
+
+	// Contains uppercase letters or special characters
+	for _, r := range s {
+		if unicode.IsUpper(r) {
+			needsQuoting = true
+			break
+		}
+		if !unicode.IsLetter(r) && !unicode.IsDigit(r) && r != '_' {
+			needsQuoting = true
+			break
+		}
+	}
+
+	if needsQuoting {
+		// Escape double quotes by doubling them
+		escaped := strings.ReplaceAll(s, `"`, `""`)
+		return `"` + escaped + `"`
+	}
+
+	return s
+}
+
 // Type conversion functions
 
 // goTypeToSQL converts Go type to PostgreSQL type

pkg/writers/pgsql/template_functions_test.go

@@ -101,6 +101,31 @@ func TestSafeIdentifier(t *testing.T) {
 	}
 }
 
+func TestQuoteIdent(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"valid_name", "valid_name"},
+		{"ValidName", `"ValidName"`},
+		{"123column", `"123column"`},
+		{"215162_fk_constraint", `"215162_fk_constraint"`},
+		{"user-id", `"user-id"`},
+		{"user@domain", `"user@domain"`},
+		{`"quoted"`, `"""quoted"""`},
+		{"", `""`},
+		{"lowercase", "lowercase"},
+		{"with_underscore", "with_underscore"},
+	}
+
+	for _, tt := range tests {
+		result := quoteIdent(tt.input)
+		if result != tt.expected {
+			t.Errorf("quoteIdent(%q) = %q, want %q", tt.input, result, tt.expected)
+		}
+	}
+}
+
 func TestGoTypeToSQL(t *testing.T) {
 	tests := []struct {
 		input    string
@@ -243,7 +268,7 @@ func TestTemplateFunctions(t *testing.T) {
 	// Check that all expected functions are registered
 	expectedFuncs := []string{
 		"upper", "lower", "snake_case", "camelCase",
-		"indent", "quote", "escape", "safe_identifier",
+		"indent", "quote", "escape", "safe_identifier", "quote_ident",
 		"goTypeToSQL", "sqlTypeToGo", "isNumeric", "isText",
 		"first", "last", "filter", "mapFunc", "join_with",
 		"join",

pkg/writers/pgsql/templates.go

@@ -177,6 +177,72 @@ type AuditTriggerData struct {
 	Events       string
 }
 
+// CreateUniqueConstraintData contains data for create unique constraint template
+type CreateUniqueConstraintData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	Columns        string
+}
+
+// CreateCheckConstraintData contains data for create check constraint template
+type CreateCheckConstraintData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	Expression     string
+}
+
+// CreateForeignKeyWithCheckData contains data for create foreign key with existence check template
+type CreateForeignKeyWithCheckData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	SourceColumns  string
+	TargetSchema   string
+	TargetTable    string
+	TargetColumns  string
+	OnDelete       string
+	OnUpdate       string
+	Deferrable     bool
+}
+
+// SetSequenceValueData contains data for set sequence value template
+type SetSequenceValueData struct {
+	SchemaName   string
+	TableName    string
+	SequenceName string
+	ColumnName   string
+}
+
+// CreateSequenceData contains data for create sequence template
+type CreateSequenceData struct {
+	SchemaName   string
+	SequenceName string
+	Increment    int
+	MinValue     int64
+	MaxValue     int64
+	StartValue   int64
+	CacheSize    int
+}
+
+// AddColumnWithCheckData contains data for add column with existence check template
+type AddColumnWithCheckData struct {
+	SchemaName       string
+	TableName        string
+	ColumnName       string
+	ColumnDefinition string
+}
+
+// CreatePrimaryKeyWithAutoGenCheckData contains data for primary key with auto-generated key check template
+type CreatePrimaryKeyWithAutoGenCheckData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	AutoGenNames   string // Comma-separated list of names like "'name1', 'name2'"
+	Columns        string
+}
+
 // Execute methods for each template
 
 // ExecuteCreateTable executes the create table template
@@ -319,6 +385,76 @@ func (te *TemplateExecutor) ExecuteAuditTrigger(data AuditTriggerData) (string,
 	return buf.String(), nil
 }
 
+// ExecuteCreateUniqueConstraint executes the create unique constraint template
+func (te *TemplateExecutor) ExecuteCreateUniqueConstraint(data CreateUniqueConstraintData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_unique_constraint.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_unique_constraint template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateCheckConstraint executes the create check constraint template
+func (te *TemplateExecutor) ExecuteCreateCheckConstraint(data CreateCheckConstraintData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_check_constraint.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_check_constraint template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateForeignKeyWithCheck executes the create foreign key with check template
+func (te *TemplateExecutor) ExecuteCreateForeignKeyWithCheck(data CreateForeignKeyWithCheckData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_foreign_key_with_check.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_foreign_key_with_check template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteSetSequenceValue executes the set sequence value template
+func (te *TemplateExecutor) ExecuteSetSequenceValue(data SetSequenceValueData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "set_sequence_value.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute set_sequence_value template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateSequence executes the create sequence template
+func (te *TemplateExecutor) ExecuteCreateSequence(data CreateSequenceData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_sequence.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_sequence template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteAddColumnWithCheck executes the add column with check template
+func (te *TemplateExecutor) ExecuteAddColumnWithCheck(data AddColumnWithCheckData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "add_column_with_check.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute add_column_with_check template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreatePrimaryKeyWithAutoGenCheck executes the create primary key with auto-generated key check template
+func (te *TemplateExecutor) ExecuteCreatePrimaryKeyWithAutoGenCheck(data CreatePrimaryKeyWithAutoGenCheckData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_primary_key_with_autogen_check.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_primary_key_with_autogen_check template: %w", err)
+	}
+	return buf.String(), nil
+}
+
 // Helper functions to build template data from models
 
 // BuildCreateTableData builds CreateTableData from a models.Table

pkg/writers/pgsql/templates/add_column.tmpl

@@ -1,4 +1,4 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ADD COLUMN IF NOT EXISTS {{.ColumnName}} {{.ColumnType}}
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+  ADD COLUMN IF NOT EXISTS {{quote_ident .ColumnName}} {{.ColumnType}}
 {{- if .Default}} DEFAULT {{.Default}}{{end}}
 {{- if .NotNull}} NOT NULL{{end}};

pkg/writers/pgsql/templates/add_column_with_check.tmpl

@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND column_name = '{{.ColumnName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD COLUMN {{.ColumnDefinition}};
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/alter_column_default.tmpl

@@ -1,7 +1,7 @@
 {{- if .SetDefault -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ALTER COLUMN {{.ColumnName}} SET DEFAULT {{.DefaultValue}};
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+  ALTER COLUMN {{quote_ident .ColumnName}} SET DEFAULT {{.DefaultValue}};
 {{- else -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ALTER COLUMN {{.ColumnName}} DROP DEFAULT;
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+  ALTER COLUMN {{quote_ident .ColumnName}} DROP DEFAULT;
 {{- end -}}

pkg/writers/pgsql/templates/alter_column_type.tmpl

@@ -1,2 +1,2 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ALTER COLUMN {{.ColumnName}} TYPE {{.NewType}};
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+  ALTER COLUMN {{quote_ident .ColumnName}} TYPE {{.NewType}};

pkg/writers/pgsql/templates/comment_column.tmpl

@@ -1 +1 @@
-COMMENT ON COLUMN {{.SchemaName}}.{{.TableName}}.{{.ColumnName}} IS '{{.Comment}}';
+COMMENT ON COLUMN {{quote_ident .SchemaName}}.{{quote_ident .TableName}}.{{quote_ident .ColumnName}} IS '{{.Comment}}';

pkg/writers/pgsql/templates/comment_table.tmpl

@@ -1 +1 @@
-COMMENT ON TABLE {{.SchemaName}}.{{.TableName}} IS '{{.Comment}}';
+COMMENT ON TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} IS '{{.Comment}}';

pkg/writers/pgsql/templates/create_check_constraint.tmpl

@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} CHECK ({{.Expression}});
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/create_foreign_key.tmpl

@@ -1,10 +1,10 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  DROP CONSTRAINT IF EXISTS {{.ConstraintName}};
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+  DROP CONSTRAINT IF EXISTS {{quote_ident .ConstraintName}};
 
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ADD CONSTRAINT {{.ConstraintName}}
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+  ADD CONSTRAINT {{quote_ident .ConstraintName}}
   FOREIGN KEY ({{.SourceColumns}})
-  REFERENCES {{.TargetSchema}}.{{.TargetTable}} ({{.TargetColumns}})
+  REFERENCES {{quote_ident .TargetSchema}}.{{quote_ident .TargetTable}} ({{.TargetColumns}})
   ON DELETE {{.OnDelete}}
   ON UPDATE {{.OnUpdate}}
   DEFERRABLE;

pkg/writers/pgsql/templates/create_foreign_key_with_check.tmpl

@@ -0,0 +1,18 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+      ADD CONSTRAINT {{quote_ident .ConstraintName}}
+      FOREIGN KEY ({{.SourceColumns}})
+      REFERENCES {{quote_ident .TargetSchema}}.{{quote_ident .TargetTable}} ({{.TargetColumns}})
+      ON DELETE {{.OnDelete}}
+      ON UPDATE {{.OnUpdate}}{{if .Deferrable}}
+      DEFERRABLE{{end}};
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/create_index.tmpl

@@ -1,2 +1,2 @@
-CREATE {{if .Unique}}UNIQUE {{end}}INDEX IF NOT EXISTS {{.IndexName}}
-  ON {{.SchemaName}}.{{.TableName}} USING {{.IndexType}} ({{.Columns}});
+CREATE {{if .Unique}}UNIQUE {{end}}INDEX IF NOT EXISTS {{quote_ident .IndexName}}
+  ON {{quote_ident .SchemaName}}.{{quote_ident .TableName}} USING {{.IndexType}} ({{.Columns}});

pkg/writers/pgsql/templates/create_primary_key.tmpl

@@ -6,8 +6,8 @@ BEGIN
       AND table_name = '{{.TableName}}'
       AND constraint_name = '{{.ConstraintName}}'
   ) THEN
-    ALTER TABLE {{.SchemaName}}.{{.TableName}}
-      ADD CONSTRAINT {{.ConstraintName}} PRIMARY KEY ({{.Columns}});
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+      ADD CONSTRAINT {{quote_ident .ConstraintName}} PRIMARY KEY ({{.Columns}});
   END IF;
 END;
 $$;

pkg/writers/pgsql/templates/create_primary_key_with_autogen_check.tmpl

@@ -0,0 +1,27 @@
+DO $$
+DECLARE
+  auto_pk_name text;
+BEGIN
+  -- Drop auto-generated primary key if it exists
+  SELECT constraint_name INTO auto_pk_name
+  FROM information_schema.table_constraints
+  WHERE table_schema = '{{.SchemaName}}'
+    AND table_name = '{{.TableName}}'
+    AND constraint_type = 'PRIMARY KEY'
+    AND constraint_name IN ({{.AutoGenNames}});
+
+  IF auto_pk_name IS NOT NULL THEN
+    EXECUTE 'ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} DROP CONSTRAINT ' || quote_ident(auto_pk_name);
+  END IF;
+
+  -- Add named primary key if it doesn't exist
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} PRIMARY KEY ({{.Columns}});
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/create_sequence.tmpl

@@ -0,0 +1,6 @@
+CREATE SEQUENCE IF NOT EXISTS {{quote_ident .SchemaName}}.{{quote_ident .SequenceName}}
+  INCREMENT {{.Increment}}
+  MINVALUE {{.MinValue}}
+  MAXVALUE {{.MaxValue}}
+  START {{.StartValue}}
+  CACHE {{.CacheSize}};

pkg/writers/pgsql/templates/create_table.tmpl

@@ -1,7 +1,7 @@
-CREATE TABLE IF NOT EXISTS {{.SchemaName}}.{{.TableName}} (
+CREATE TABLE IF NOT EXISTS {{quote_ident .SchemaName}}.{{quote_ident .TableName}} (
 {{- range $i, $col := .Columns}}
 {{- if $i}},{{end}}
-  {{$col.Name}} {{$col.Type}}
+  {{quote_ident $col.Name}} {{$col.Type}}
 {{- if $col.Default}} DEFAULT {{$col.Default}}{{end}}
 {{- if $col.NotNull}} NOT NULL{{end}}
 {{- end}}

pkg/writers/pgsql/templates/create_unique_constraint.tmpl

@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} UNIQUE ({{.Columns}});
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/drop_constraint.tmpl

@@ -1 +1 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}} DROP CONSTRAINT IF EXISTS {{.ConstraintName}};
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} DROP CONSTRAINT IF EXISTS {{quote_ident .ConstraintName}};

pkg/writers/pgsql/templates/drop_index.tmpl

@@ -1 +1 @@
-DROP INDEX IF EXISTS {{.SchemaName}}.{{.IndexName}} CASCADE;
+DROP INDEX IF EXISTS {{quote_ident .SchemaName}}.{{quote_ident .IndexName}} CASCADE;

pkg/writers/pgsql/templates/set_sequence_value.tmpl

@@ -0,0 +1,19 @@
+DO $$
+DECLARE
+  m_cnt bigint;
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM pg_class c
+    INNER JOIN pg_namespace n ON n.oid = c.relnamespace
+    WHERE c.relname = '{{.SequenceName}}'
+      AND n.nspname = '{{.SchemaName}}'
+      AND c.relkind = 'S'
+  ) THEN
+    SELECT COALESCE(MAX({{quote_ident .ColumnName}}), 0) + 1
+    FROM {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+    INTO m_cnt;
+    
+    PERFORM setval('{{quote_ident .SchemaName}}.{{quote_ident .SequenceName}}'::regclass, m_cnt);
+  END IF;
+END;
+$$;

pkg/writers/pgsql/writer.go

@@ -22,6 +22,7 @@ type Writer struct {
 	options         *writers.WriterOptions
 	writer          io.Writer
 	executionReport *ExecutionReport
+	executor        *TemplateExecutor
 }
 
 // ExecutionReport tracks the execution status of SQL statements
@@ -57,8 +58,10 @@ type ExecutionError struct {
 
 // NewWriter creates a new PostgreSQL SQL writer
 func NewWriter(options *writers.WriterOptions) *Writer {
+	executor, _ := NewTemplateExecutor()
 	return &Writer{
-		options: options,
+		options:  options,
+		executor: executor,
 	}
 }
 
@@ -215,36 +218,19 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				fmt.Sprintf("%s_%s_pkey", schema.Name, table.Name),
 			}
 
-			// Wrap in DO block to drop auto-generated PK and add our named PK
-			stmt := fmt.Sprintf("DO $$\nDECLARE\n"+
-				"  auto_pk_name text;\n"+
-				"BEGIN\n"+
-				"  -- Drop auto-generated primary key if it exists\n"+
-				"  SELECT constraint_name INTO auto_pk_name\n"+
-				"  FROM information_schema.table_constraints\n"+
-				"  WHERE table_schema = '%s'\n"+
-				"    AND table_name = '%s'\n"+
-				"    AND constraint_type = 'PRIMARY KEY'\n"+
-				"    AND constraint_name IN (%s);\n"+
-				"\n"+
-				"  IF auto_pk_name IS NOT NULL THEN\n"+
-				"    EXECUTE 'ALTER TABLE %s.%s DROP CONSTRAINT ' || quote_ident(auto_pk_name);\n"+
-				"  END IF;\n"+
-				"\n"+
-				"  -- Add named primary key if it doesn't exist\n"+
-				"  IF NOT EXISTS (\n"+
-				"    SELECT 1 FROM information_schema.table_constraints\n"+
-				"    WHERE table_schema = '%s'\n"+
-				"      AND table_name = '%s'\n"+
-				"      AND constraint_name = '%s'\n"+
-				"  ) THEN\n"+
-				"    ALTER TABLE %s.%s ADD CONSTRAINT %s PRIMARY KEY (%s);\n"+
-				"  END IF;\n"+
-				"END;\n$$",
-				schema.Name, table.Name, formatStringList(autoGenPKNames),
-				schema.SQLName(), table.SQLName(),
-				schema.Name, table.Name, pkName,
-				schema.SQLName(), table.SQLName(), pkName, strings.Join(pkColumns, ", "))
+			// Use template to generate primary key statement
+			data := CreatePrimaryKeyWithAutoGenCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: pkName,
+				AutoGenNames:   formatStringList(autoGenPKNames),
+				Columns:        strings.Join(pkColumns, ", "),
+			}
+
+			stmt, err := w.executor.ExecuteCreatePrimaryKeyWithAutoGenCheck(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate primary key for %s.%s: %w", schema.Name, table.Name, err)
+			}
 			statements = append(statements, stmt)
 		}
 	}
@@ -290,7 +276,7 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 			}
 
 			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s.%s USING %s (%s)%s",
-				uniqueStr, index.Name, schema.SQLName(), table.SQLName(), indexType, strings.Join(columnExprs, ", "), whereClause)
+				uniqueStr, quoteIdentifier(index.Name), schema.SQLName(), table.SQLName(), indexType, strings.Join(columnExprs, ", "), whereClause)
 			statements = append(statements, stmt)
 		}
 	}
@@ -302,20 +288,41 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				continue
 			}
 
-			// Wrap in DO block to check for existing constraint
-			stmt := fmt.Sprintf("DO $$\nBEGIN\n"+
-				"  IF NOT EXISTS (\n"+
-				"    SELECT 1 FROM information_schema.table_constraints\n"+
-				"    WHERE table_schema = '%s'\n"+
-				"      AND table_name = '%s'\n"+
-				"      AND constraint_name = '%s'\n"+
-				"  ) THEN\n"+
-				"    ALTER TABLE %s.%s ADD CONSTRAINT %s UNIQUE (%s);\n"+
-				"  END IF;\n"+
-				"END;\n$$",
-				schema.Name, table.Name, constraint.Name,
-				schema.SQLName(), table.SQLName(), constraint.Name,
-				strings.Join(constraint.Columns, ", "))
+			// Use template to generate unique constraint statement
+			data := CreateUniqueConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Columns:        strings.Join(constraint.Columns, ", "),
+			}
+
+			stmt, err := w.executor.ExecuteCreateUniqueConstraint(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate unique constraint for %s.%s: %w", schema.Name, table.Name, err)
+			}
+			statements = append(statements, stmt)
+		}
+	}
+
+	// Phase 5.7: Check constraints
+	for _, table := range schema.Tables {
+		for _, constraint := range table.Constraints {
+			if constraint.Type != models.CheckConstraint {
+				continue
+			}
+
+			// Use template to generate check constraint statement
+			data := CreateCheckConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Expression:     constraint.Expression,
+			}
+
+			stmt, err := w.executor.ExecuteCreateCheckConstraint(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate check constraint for %s.%s: %w", schema.Name, table.Name, err)
+			}
 			statements = append(statements, stmt)
 		}
 	}
@@ -342,23 +349,24 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				onUpdate = "NO ACTION"
 			}
 
-			// Wrap in DO block to check for existing constraint
-			stmt := fmt.Sprintf("DO $$\nBEGIN\n"+
-				"  IF NOT EXISTS (\n"+
-				"    SELECT 1 FROM information_schema.table_constraints\n"+
-				"    WHERE table_schema = '%s'\n"+
-				"      AND table_name = '%s'\n"+
-				"      AND constraint_name = '%s'\n"+
-				"  ) THEN\n"+
-				"    ALTER TABLE %s.%s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s.%s(%s) ON DELETE %s ON UPDATE %s;\n"+
-				"  END IF;\n"+
-				"END;\n$$",
-				schema.Name, table.Name, constraint.Name,
-				schema.SQLName(), table.SQLName(), constraint.Name,
-				strings.Join(constraint.Columns, ", "),
-				strings.ToLower(refSchema), strings.ToLower(constraint.ReferencedTable),
-				strings.Join(constraint.ReferencedColumns, ", "),
-				onDelete, onUpdate)
+			// Use template to generate foreign key statement
+			data := CreateForeignKeyWithCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				SourceColumns:  strings.Join(constraint.Columns, ", "),
+				TargetSchema:   refSchema,
+				TargetTable:    constraint.ReferencedTable,
+				TargetColumns:  strings.Join(constraint.ReferencedColumns, ", "),
+				OnDelete:       onDelete,
+				OnUpdate:       onUpdate,
+				Deferrable:     false,
+			}
+
+			stmt, err := w.executor.ExecuteCreateForeignKeyWithCheck(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate foreign key for %s.%s: %w", schema.Name, table.Name, err)
+			}
 			statements = append(statements, stmt)
 		}
 	}
@@ -406,19 +414,18 @@ func (w *Writer) GenerateAddColumnStatements(schema *models.Schema) ([]string, e
 		for _, col := range columns {
 			colDef := w.generateColumnDefinition(col)
 
-			// Generate DO block that checks if column exists before adding
-			stmt := fmt.Sprintf("DO $$\nBEGIN\n"+
-				"  IF NOT EXISTS (\n"+
-				"    SELECT 1 FROM information_schema.columns\n"+
-				"    WHERE table_schema = '%s'\n"+
-				"      AND table_name = '%s'\n"+
-				"      AND column_name = '%s'\n"+
-				"  ) THEN\n"+
-				"    ALTER TABLE %s.%s ADD COLUMN %s;\n"+
-				"  END IF;\n"+
-				"END;\n$$",
-				schema.Name, table.Name, col.Name,
-				schema.SQLName(), table.SQLName(), colDef)
+			// Use template to generate add column statement
+			data := AddColumnWithCheckData{
+				SchemaName:       schema.Name,
+				TableName:        table.Name,
+				ColumnName:       col.Name,
+				ColumnDefinition: colDef,
+			}
+
+			stmt, err := w.executor.ExecuteAddColumnWithCheck(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate add column for %s.%s.%s: %w", schema.Name, table.Name, col.Name, err)
+			}
 			statements = append(statements, stmt)
 		}
 	}
@@ -572,6 +579,11 @@ func (w *Writer) WriteSchema(schema *models.Schema) error {
 		return err
 	}
 
+	// Phase 5.7: Create check constraints (priority 190)
+	if err := w.writeCheckConstraints(schema); err != nil {
+		return err
+	}
+
 	// Phase 6: Create foreign key constraints (priority 195)
 	if err := w.writeForeignKeys(schema); err != nil {
 		return err
@@ -669,13 +681,23 @@ func (w *Writer) writeSequences(schema *models.Schema) error {
 		}
 
 		seqName := fmt.Sprintf("identity_%s_%s", table.SQLName(), pk.SQLName())
-		fmt.Fprintf(w.writer, "CREATE SEQUENCE IF NOT EXISTS %s.%s\n",
-			schema.SQLName(), seqName)
-		fmt.Fprintf(w.writer, "  INCREMENT 1\n")
-		fmt.Fprintf(w.writer, "  MINVALUE 1\n")
-		fmt.Fprintf(w.writer, "  MAXVALUE 9223372036854775807\n")
-		fmt.Fprintf(w.writer, "  START 1\n")
-		fmt.Fprintf(w.writer, "  CACHE 1;\n\n")
+
+		data := CreateSequenceData{
+			SchemaName:   schema.Name,
+			SequenceName: seqName,
+			Increment:    1,
+			MinValue:     1,
+			MaxValue:     9223372036854775807,
+			StartValue:   1,
+			CacheSize:    1,
+		}
+
+		sql, err := w.executor.ExecuteCreateSequence(data)
+		if err != nil {
+			return fmt.Errorf("failed to generate create sequence for %s.%s: %w", schema.Name, seqName, err)
+		}
+		fmt.Fprint(w.writer, sql)
+		fmt.Fprint(w.writer, "\n")
 	}
 
 	return nil
@@ -717,18 +739,19 @@ func (w *Writer) writeAddColumns(schema *models.Schema) error {
 		for _, col := range columns {
 			colDef := w.generateColumnDefinition(col)
 
-			// Generate DO block that checks if column exists before adding
-			fmt.Fprintf(w.writer, "DO $$\nBEGIN\n")
-			fmt.Fprintf(w.writer, "  IF NOT EXISTS (\n")
-			fmt.Fprintf(w.writer, "    SELECT 1 FROM information_schema.columns\n")
-			fmt.Fprintf(w.writer, "    WHERE table_schema = '%s'\n", schema.Name)
-			fmt.Fprintf(w.writer, "      AND table_name = '%s'\n", table.Name)
-			fmt.Fprintf(w.writer, "      AND column_name = '%s'\n", col.Name)
-			fmt.Fprintf(w.writer, "  ) THEN\n")
-			fmt.Fprintf(w.writer, "    ALTER TABLE %s.%s ADD COLUMN %s;\n",
-				schema.SQLName(), table.SQLName(), colDef)
-			fmt.Fprintf(w.writer, "  END IF;\n")
-			fmt.Fprintf(w.writer, "END;\n$$;\n\n")
+			data := AddColumnWithCheckData{
+				SchemaName:       schema.Name,
+				TableName:        table.Name,
+				ColumnName:       col.Name,
+				ColumnDefinition: colDef,
+			}
+
+			sql, err := w.executor.ExecuteAddColumnWithCheck(data)
+			if err != nil {
+				return fmt.Errorf("failed to generate add column for %s.%s.%s: %w", schema.Name, table.Name, col.Name, err)
+			}
+			fmt.Fprint(w.writer, sql)
+			fmt.Fprint(w.writer, "\n")
 		}
 	}
 
@@ -782,37 +805,20 @@ func (w *Writer) writePrimaryKeys(schema *models.Schema) error {
 			fmt.Sprintf("%s_%s_pkey", schema.Name, table.Name),
 		}
 
-		fmt.Fprintf(w.writer, "DO $$\nDECLARE\n")
-		fmt.Fprintf(w.writer, "  auto_pk_name text;\nBEGIN\n")
+		data := CreatePrimaryKeyWithAutoGenCheckData{
+			SchemaName:     schema.Name,
+			TableName:      table.Name,
+			ConstraintName: pkName,
+			AutoGenNames:   formatStringList(autoGenPKNames),
+			Columns:        strings.Join(columnNames, ", "),
+		}
 
-		// Check for and drop auto-generated primary keys
-		fmt.Fprintf(w.writer, "  -- Drop auto-generated primary key if it exists\n")
-		fmt.Fprintf(w.writer, "  SELECT constraint_name INTO auto_pk_name\n")
-		fmt.Fprintf(w.writer, "  FROM information_schema.table_constraints\n")
-		fmt.Fprintf(w.writer, "  WHERE table_schema = '%s'\n", schema.Name)
-		fmt.Fprintf(w.writer, "    AND table_name = '%s'\n", table.Name)
-		fmt.Fprintf(w.writer, "    AND constraint_type = 'PRIMARY KEY'\n")
-		fmt.Fprintf(w.writer, "    AND constraint_name IN (%s);\n", formatStringList(autoGenPKNames))
-		fmt.Fprintf(w.writer, "\n")
-		fmt.Fprintf(w.writer, "  IF auto_pk_name IS NOT NULL THEN\n")
-		fmt.Fprintf(w.writer, "    EXECUTE 'ALTER TABLE %s.%s DROP CONSTRAINT ' || quote_ident(auto_pk_name);\n",
-			schema.SQLName(), table.SQLName())
-		fmt.Fprintf(w.writer, "  END IF;\n")
-		fmt.Fprintf(w.writer, "\n")
-
-		// Add our named primary key if it doesn't exist
-		fmt.Fprintf(w.writer, "  -- Add named primary key if it doesn't exist\n")
-		fmt.Fprintf(w.writer, "  IF NOT EXISTS (\n")
-		fmt.Fprintf(w.writer, "    SELECT 1 FROM information_schema.table_constraints\n")
-		fmt.Fprintf(w.writer, "    WHERE table_schema = '%s'\n", schema.Name)
-		fmt.Fprintf(w.writer, "      AND table_name = '%s'\n", table.Name)
-		fmt.Fprintf(w.writer, "      AND constraint_name = '%s'\n", pkName)
-		fmt.Fprintf(w.writer, "  ) THEN\n")
-		fmt.Fprintf(w.writer, "    ALTER TABLE %s.%s\n", schema.SQLName(), table.SQLName())
-		fmt.Fprintf(w.writer, "      ADD CONSTRAINT %s PRIMARY KEY (%s);\n",
-			pkName, strings.Join(columnNames, ", "))
-		fmt.Fprintf(w.writer, "  END IF;\n")
-		fmt.Fprintf(w.writer, "END;\n$$;\n\n")
+		sql, err := w.executor.ExecuteCreatePrimaryKeyWithAutoGenCheck(data)
+		if err != nil {
+			return fmt.Errorf("failed to generate primary key for %s.%s: %w", schema.Name, table.Name, err)
+		}
+		fmt.Fprint(w.writer, sql)
+		fmt.Fprint(w.writer, "\n")
 	}
 
 	return nil
@@ -924,20 +930,56 @@ func (w *Writer) writeUniqueConstraints(schema *models.Schema) error {
 				continue
 			}
 
-			// Wrap in DO block to check for existing constraint
-			fmt.Fprintf(w.writer, "DO $$\n")
-			fmt.Fprintf(w.writer, "BEGIN\n")
-			fmt.Fprintf(w.writer, "  IF NOT EXISTS (\n")
-			fmt.Fprintf(w.writer, "    SELECT 1 FROM information_schema.table_constraints\n")
-			fmt.Fprintf(w.writer, "    WHERE table_schema = '%s'\n", schema.Name)
-			fmt.Fprintf(w.writer, "      AND table_name = '%s'\n", table.Name)
-			fmt.Fprintf(w.writer, "      AND constraint_name = '%s'\n", constraint.Name)
-			fmt.Fprintf(w.writer, "  ) THEN\n")
-			fmt.Fprintf(w.writer, "    ALTER TABLE %s.%s ADD CONSTRAINT %s UNIQUE (%s);\n",
-				schema.SQLName(), table.SQLName(), constraint.Name, strings.Join(columnExprs, ", "))
-			fmt.Fprintf(w.writer, "  END IF;\n")
-			fmt.Fprintf(w.writer, "END;\n")
-			fmt.Fprintf(w.writer, "$$;\n\n")
+			sql, err := w.executor.ExecuteCreateUniqueConstraint(CreateUniqueConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Columns:        strings.Join(columnExprs, ", "),
+			})
+			if err != nil {
+				return fmt.Errorf("failed to generate unique constraint: %w", err)
+			}
+
+			fmt.Fprintf(w.writer, "%s\n\n", sql)
+		}
+	}
+
+	return nil
+}
+
+// writeCheckConstraints generates ALTER TABLE statements for check constraints
+func (w *Writer) writeCheckConstraints(schema *models.Schema) error {
+	fmt.Fprintf(w.writer, "-- Check constraints for schema: %s\n", schema.Name)
+
+	for _, table := range schema.Tables {
+		// Sort constraints by name for consistent output
+		constraintNames := make([]string, 0, len(table.Constraints))
+		for name, constraint := range table.Constraints {
+			if constraint.Type == models.CheckConstraint {
+				constraintNames = append(constraintNames, name)
+			}
+		}
+		sort.Strings(constraintNames)
+
+		for _, name := range constraintNames {
+			constraint := table.Constraints[name]
+
+			// Skip if expression is empty
+			if constraint.Expression == "" {
+				continue
+			}
+
+			sql, err := w.executor.ExecuteCreateCheckConstraint(CreateCheckConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Expression:     constraint.Expression,
+			})
+			if err != nil {
+				return fmt.Errorf("failed to generate check constraint: %w", err)
+			}
+
+			fmt.Fprintf(w.writer, "%s\n\n", sql)
 		}
 	}
 
@@ -1021,24 +1063,103 @@ func (w *Writer) writeForeignKeys(schema *models.Schema) error {
 				refTable = rel.ToTable
 			}
 
-			// Use DO block to check if constraint exists before adding
-			fmt.Fprintf(w.writer, "DO $$\nBEGIN\n")
-			fmt.Fprintf(w.writer, "  IF NOT EXISTS (\n")
-			fmt.Fprintf(w.writer, "    SELECT 1 FROM information_schema.table_constraints\n")
-			fmt.Fprintf(w.writer, "    WHERE table_schema = '%s'\n", schema.Name)
-			fmt.Fprintf(w.writer, "      AND table_name = '%s'\n", table.Name)
-			fmt.Fprintf(w.writer, "      AND constraint_name = '%s'\n", fkName)
-			fmt.Fprintf(w.writer, "  ) THEN\n")
-			fmt.Fprintf(w.writer, "    ALTER TABLE %s.%s\n", schema.SQLName(), table.SQLName())
-			fmt.Fprintf(w.writer, "      ADD CONSTRAINT %s\n", fkName)
-			fmt.Fprintf(w.writer, "      FOREIGN KEY (%s)\n", strings.Join(sourceColumns, ", "))
-			fmt.Fprintf(w.writer, "      REFERENCES %s.%s (%s)\n",
-				refSchema, refTable, strings.Join(targetColumns, ", "))
-			fmt.Fprintf(w.writer, "      ON DELETE %s\n", onDelete)
-			fmt.Fprintf(w.writer, "      ON UPDATE %s\n", onUpdate)
-			fmt.Fprintf(w.writer, "      DEFERRABLE;\n")
-			fmt.Fprintf(w.writer, "  END IF;\n")
-			fmt.Fprintf(w.writer, "END;\n$$;\n\n")
+			// Use template executor to generate foreign key with existence check
+			data := CreateForeignKeyWithCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: fkName,
+				SourceColumns:  strings.Join(sourceColumns, ", "),
+				TargetSchema:   refSchema,
+				TargetTable:    refTable,
+				TargetColumns:  strings.Join(targetColumns, ", "),
+				OnDelete:       onDelete,
+				OnUpdate:       onUpdate,
+				Deferrable:     true,
+			}
+			sql, err := w.executor.ExecuteCreateForeignKeyWithCheck(data)
+			if err != nil {
+				return fmt.Errorf("failed to generate foreign key for %s.%s: %w", schema.Name, table.Name, err)
+			}
+			fmt.Fprint(w.writer, sql)
+		}
+
+		// Also process any foreign key constraints that don't have a relationship
+		processedConstraints := make(map[string]bool)
+		for _, rel := range table.Relationships {
+			fkName := rel.ForeignKey
+			if fkName == "" {
+				fkName = rel.Name
+			}
+			if fkName != "" {
+				processedConstraints[fkName] = true
+			}
+		}
+
+		// Find unprocessed foreign key constraints
+		constraintNames := make([]string, 0)
+		for name, constraint := range table.Constraints {
+			if constraint.Type == models.ForeignKeyConstraint && !processedConstraints[name] {
+				constraintNames = append(constraintNames, name)
+			}
+		}
+		sort.Strings(constraintNames)
+
+		for _, name := range constraintNames {
+			constraint := table.Constraints[name]
+
+			// Build column lists
+			sourceColumns := make([]string, 0, len(constraint.Columns))
+			for _, colName := range constraint.Columns {
+				if col, ok := table.Columns[colName]; ok {
+					sourceColumns = append(sourceColumns, col.SQLName())
+				} else {
+					sourceColumns = append(sourceColumns, colName)
+				}
+			}
+
+			targetColumns := make([]string, 0, len(constraint.ReferencedColumns))
+			for _, colName := range constraint.ReferencedColumns {
+				targetColumns = append(targetColumns, strings.ToLower(colName))
+			}
+
+			if len(sourceColumns) == 0 || len(targetColumns) == 0 {
+				continue
+			}
+
+			onDelete := "NO ACTION"
+			if constraint.OnDelete != "" {
+				onDelete = strings.ToUpper(constraint.OnDelete)
+			}
+
+			onUpdate := "NO ACTION"
+			if constraint.OnUpdate != "" {
+				onUpdate = strings.ToUpper(constraint.OnUpdate)
+			}
+
+			refSchema := constraint.ReferencedSchema
+			if refSchema == "" {
+				refSchema = schema.Name
+			}
+			refTable := constraint.ReferencedTable
+
+			// Use template executor to generate foreign key with existence check
+			data := CreateForeignKeyWithCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				SourceColumns:  strings.Join(sourceColumns, ", "),
+				TargetSchema:   refSchema,
+				TargetTable:    refTable,
+				TargetColumns:  strings.Join(targetColumns, ", "),
+				OnDelete:       onDelete,
+				OnUpdate:       onUpdate,
+				Deferrable:     false,
+			}
+			sql, err := w.executor.ExecuteCreateForeignKeyWithCheck(data)
+			if err != nil {
+				return fmt.Errorf("failed to generate foreign key for %s.%s: %w", schema.Name, table.Name, err)
+			}
+			fmt.Fprint(w.writer, sql)
 		}
 	}
 
@@ -1057,26 +1178,19 @@ func (w *Writer) writeSetSequenceValues(schema *models.Schema) error {
 
 		seqName := fmt.Sprintf("identity_%s_%s", table.SQLName(), pk.SQLName())
 
-		fmt.Fprintf(w.writer, "DO $$\n")
-		fmt.Fprintf(w.writer, "DECLARE\n")
-		fmt.Fprintf(w.writer, "  m_cnt bigint;\n")
-		fmt.Fprintf(w.writer, "BEGIN\n")
-		fmt.Fprintf(w.writer, "  IF EXISTS (\n")
-		fmt.Fprintf(w.writer, "    SELECT 1 FROM pg_class c\n")
-		fmt.Fprintf(w.writer, "    INNER JOIN pg_namespace n ON n.oid = c.relnamespace\n")
-		fmt.Fprintf(w.writer, "    WHERE c.relname = '%s'\n", seqName)
-		fmt.Fprintf(w.writer, "      AND n.nspname = '%s'\n", schema.Name)
-		fmt.Fprintf(w.writer, "      AND c.relkind = 'S'\n")
-		fmt.Fprintf(w.writer, "  ) THEN\n")
-		fmt.Fprintf(w.writer, "    SELECT COALESCE(MAX(%s), 0) + 1\n", pk.SQLName())
-		fmt.Fprintf(w.writer, "    FROM %s.%s\n", schema.SQLName(), table.SQLName())
-		fmt.Fprintf(w.writer, "    INTO m_cnt;\n")
-		fmt.Fprintf(w.writer, "    \n")
-		fmt.Fprintf(w.writer, "    PERFORM setval('%s.%s'::regclass, m_cnt);\n",
-			schema.SQLName(), seqName)
-		fmt.Fprintf(w.writer, "  END IF;\n")
-		fmt.Fprintf(w.writer, "END;\n")
-		fmt.Fprintf(w.writer, "$$;\n\n")
+		// Use template executor to generate set sequence value statement
+		data := SetSequenceValueData{
+			SchemaName:   schema.Name,
+			TableName:    table.Name,
+			SequenceName: seqName,
+			ColumnName:   pk.Name,
+		}
+		sql, err := w.executor.ExecuteSetSequenceValue(data)
+		if err != nil {
+			return fmt.Errorf("failed to generate set sequence value for %s.%s: %w", schema.Name, table.Name, err)
+		}
+		fmt.Fprint(w.writer, sql)
+		fmt.Fprint(w.writer, "\n")
 	}
 
 	return nil
@@ -1296,7 +1410,8 @@ func (w *Writer) executeDatabaseSQL(db *models.Database, connString string) erro
 			continue
 		}
 
-		fmt.Fprintf(os.Stderr, "Executing statement %d/%d...\n", i+1, len(statements))
+		stmtType := detectStatementType(stmtTrimmed)
+		fmt.Fprintf(os.Stderr, "Executing statement %d/%d [%s]...\n", i+1, len(statements), stmtType)
 
 		_, execErr := conn.Exec(ctx, stmt)
 		if execErr != nil {
@@ -1430,3 +1545,94 @@ func truncateStatement(stmt string) string {
 func getCurrentTimestamp() string {
 	return time.Now().Format("2006-01-02 15:04:05")
 }
+
+// detectStatementType detects the type of SQL statement for logging
+func detectStatementType(stmt string) string {
+	upperStmt := strings.ToUpper(stmt)
+
+	// Check for DO blocks (used for conditional DDL)
+	if strings.HasPrefix(upperStmt, "DO $$") || strings.HasPrefix(upperStmt, "DO $") {
+		// Look inside the DO block for the actual operation
+		if strings.Contains(upperStmt, "ALTER TABLE") && strings.Contains(upperStmt, "ADD CONSTRAINT") {
+			if strings.Contains(upperStmt, "UNIQUE") {
+				return "ADD UNIQUE CONSTRAINT"
+			} else if strings.Contains(upperStmt, "FOREIGN KEY") {
+				return "ADD FOREIGN KEY"
+			} else if strings.Contains(upperStmt, "PRIMARY KEY") {
+				return "ADD PRIMARY KEY"
+			} else if strings.Contains(upperStmt, "CHECK") {
+				return "ADD CHECK CONSTRAINT"
+			}
+			return "ADD CONSTRAINT"
+		}
+		if strings.Contains(upperStmt, "ALTER TABLE") && strings.Contains(upperStmt, "ADD COLUMN") {
+			return "ADD COLUMN"
+		}
+		if strings.Contains(upperStmt, "DROP CONSTRAINT") {
+			return "DROP CONSTRAINT"
+		}
+		return "DO BLOCK"
+	}
+
+	// Direct DDL statements
+	if strings.HasPrefix(upperStmt, "CREATE SCHEMA") {
+		return "CREATE SCHEMA"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE SEQUENCE") {
+		return "CREATE SEQUENCE"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE TABLE") {
+		return "CREATE TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE INDEX") {
+		return "CREATE INDEX"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE UNIQUE INDEX") {
+		return "CREATE UNIQUE INDEX"
+	}
+	if strings.HasPrefix(upperStmt, "ALTER TABLE") {
+		if strings.Contains(upperStmt, "ADD CONSTRAINT") {
+			if strings.Contains(upperStmt, "FOREIGN KEY") {
+				return "ADD FOREIGN KEY"
+			} else if strings.Contains(upperStmt, "PRIMARY KEY") {
+				return "ADD PRIMARY KEY"
+			} else if strings.Contains(upperStmt, "UNIQUE") {
+				return "ADD UNIQUE CONSTRAINT"
+			} else if strings.Contains(upperStmt, "CHECK") {
+				return "ADD CHECK CONSTRAINT"
+			}
+			return "ADD CONSTRAINT"
+		}
+		if strings.Contains(upperStmt, "ADD COLUMN") {
+			return "ADD COLUMN"
+		}
+		if strings.Contains(upperStmt, "DROP CONSTRAINT") {
+			return "DROP CONSTRAINT"
+		}
+		if strings.Contains(upperStmt, "ALTER COLUMN") {
+			return "ALTER COLUMN"
+		}
+		return "ALTER TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "COMMENT ON TABLE") {
+		return "COMMENT ON TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "COMMENT ON COLUMN") {
+		return "COMMENT ON COLUMN"
+	}
+	if strings.HasPrefix(upperStmt, "DROP TABLE") {
+		return "DROP TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "DROP INDEX") {
+		return "DROP INDEX"
+	}
+
+	// Default
+	return "SQL"
+}
+
+// quoteIdentifier wraps an identifier in double quotes if necessary
+// This is needed for identifiers that start with numbers or contain special characters
+func quoteIdentifier(s string) string {
+	return quoteIdent(s)
+}

pkg/writers/pgsql/writer_test.go

@@ -234,6 +234,226 @@ func TestWriteUniqueConstraints(t *testing.T) {
 	}
 }
 
+func TestWriteCheckConstraints(t *testing.T) {
+	// Create a test database with check constraints
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create table with check constraints
+	table := models.InitTable("products", "public")
+
+	// Add columns
+	priceCol := models.InitColumn("price", "products", "public")
+	priceCol.Type = "numeric(10,2)"
+	table.Columns["price"] = priceCol
+
+	statusCol := models.InitColumn("status", "products", "public")
+	statusCol.Type = "varchar(20)"
+	table.Columns["status"] = statusCol
+
+	quantityCol := models.InitColumn("quantity", "products", "public")
+	quantityCol.Type = "integer"
+	table.Columns["quantity"] = quantityCol
+
+	// Add check constraints
+	priceConstraint := &models.Constraint{
+		Name:       "ck_price_positive",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "products",
+		Expression: "price >= 0",
+	}
+	table.Constraints["ck_price_positive"] = priceConstraint
+
+	statusConstraint := &models.Constraint{
+		Name:       "ck_status_valid",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "products",
+		Expression: "status IN ('active', 'inactive', 'discontinued')",
+	}
+	table.Constraints["ck_status_valid"] = statusConstraint
+
+	quantityConstraint := &models.Constraint{
+		Name:       "ck_quantity_nonnegative",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "products",
+		Expression: "quantity >= 0",
+	}
+	table.Constraints["ck_quantity_nonnegative"] = quantityConstraint
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write the database
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Print output for debugging
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify check constraints are present
+	if !strings.Contains(output, "-- Check constraints for schema: public") {
+		t.Errorf("Output missing check constraints header")
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT ck_price_positive CHECK (price >= 0)") {
+		t.Errorf("Output missing ck_price_positive check constraint\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT ck_status_valid CHECK (status IN ('active', 'inactive', 'discontinued'))") {
+		t.Errorf("Output missing ck_status_valid check constraint\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT ck_quantity_nonnegative CHECK (quantity >= 0)") {
+		t.Errorf("Output missing ck_quantity_nonnegative check constraint\nFull output:\n%s", output)
+	}
+}
+
+func TestWriteAllConstraintTypes(t *testing.T) {
+	// Create a comprehensive test with all constraint types
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create orders table
+	ordersTable := models.InitTable("orders", "public")
+
+	// Add columns
+	idCol := models.InitColumn("id", "orders", "public")
+	idCol.Type = "integer"
+	idCol.IsPrimaryKey = true
+	ordersTable.Columns["id"] = idCol
+
+	userIDCol := models.InitColumn("user_id", "orders", "public")
+	userIDCol.Type = "integer"
+	userIDCol.NotNull = true
+	ordersTable.Columns["user_id"] = userIDCol
+
+	orderNumberCol := models.InitColumn("order_number", "orders", "public")
+	orderNumberCol.Type = "varchar(50)"
+	orderNumberCol.NotNull = true
+	ordersTable.Columns["order_number"] = orderNumberCol
+
+	totalCol := models.InitColumn("total", "orders", "public")
+	totalCol.Type = "numeric(10,2)"
+	ordersTable.Columns["total"] = totalCol
+
+	statusCol := models.InitColumn("status", "orders", "public")
+	statusCol.Type = "varchar(20)"
+	ordersTable.Columns["status"] = statusCol
+
+	// Add primary key constraint
+	pkConstraint := &models.Constraint{
+		Name:    "pk_orders",
+		Type:    models.PrimaryKeyConstraint,
+		Schema:  "public",
+		Table:   "orders",
+		Columns: []string{"id"},
+	}
+	ordersTable.Constraints["pk_orders"] = pkConstraint
+
+	// Add unique constraint
+	uniqueConstraint := &models.Constraint{
+		Name:    "uq_order_number",
+		Type:    models.UniqueConstraint,
+		Schema:  "public",
+		Table:   "orders",
+		Columns: []string{"order_number"},
+	}
+	ordersTable.Constraints["uq_order_number"] = uniqueConstraint
+
+	// Add check constraint
+	checkConstraint := &models.Constraint{
+		Name:       "ck_total_positive",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "orders",
+		Expression: "total > 0",
+	}
+	ordersTable.Constraints["ck_total_positive"] = checkConstraint
+
+	statusCheckConstraint := &models.Constraint{
+		Name:       "ck_status_valid",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "orders",
+		Expression: "status IN ('pending', 'completed', 'cancelled')",
+	}
+	ordersTable.Constraints["ck_status_valid"] = statusCheckConstraint
+
+	// Add foreign key constraint (referencing a users table)
+	fkConstraint := &models.Constraint{
+		Name:              "fk_orders_user",
+		Type:              models.ForeignKeyConstraint,
+		Schema:            "public",
+		Table:             "orders",
+		Columns:           []string{"user_id"},
+		ReferencedSchema:  "public",
+		ReferencedTable:   "users",
+		ReferencedColumns: []string{"id"},
+		OnDelete:          "CASCADE",
+		OnUpdate:          "CASCADE",
+	}
+	ordersTable.Constraints["fk_orders_user"] = fkConstraint
+
+	schema.Tables = append(schema.Tables, ordersTable)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write the database
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Print output for debugging
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify all constraint types are present
+	expectedConstraints := map[string]string{
+		"Primary Key":      "PRIMARY KEY",
+		"Unique":           "ADD CONSTRAINT uq_order_number UNIQUE (order_number)",
+		"Check (total)":    "ADD CONSTRAINT ck_total_positive CHECK (total > 0)",
+		"Check (status)":   "ADD CONSTRAINT ck_status_valid CHECK (status IN ('pending', 'completed', 'cancelled'))",
+		"Foreign Key":      "FOREIGN KEY",
+	}
+
+	for name, expected := range expectedConstraints {
+		if !strings.Contains(output, expected) {
+			t.Errorf("Output missing %s constraint: %s\nFull output:\n%s", name, expected, output)
+		}
+	}
+
+	// Verify section headers
+	sections := []string{
+		"-- Primary keys for schema: public",
+		"-- Unique constraints for schema: public",
+		"-- Check constraints for schema: public",
+		"-- Foreign keys for schema: public",
+	}
+
+	for _, section := range sections {
+		if !strings.Contains(output, section) {
+			t.Errorf("Output missing section header: %s", section)
+		}
+	}
+}
+
 func TestWriteTable(t *testing.T) {
 	// Create a single table
 	table := models.InitTable("products", "public")