feat(pgsql): ✨ Add templates for constraints and sequences

* Introduce new templates for creating unique, check, and foreign key constraints with existence checks. * Add templates for setting sequence values and creating sequences. * Refactor existing SQL generation logic to utilize new templates for better maintainability and readability. * Ensure identifiers are properly quoted to handle special characters and reserved keywords.
feat(writer): 🎉 Add support for check constraints in schema generation
2026-01-31 21:04:43 +02:00 · 2026-01-31 20:42:19 +02:00 · 2026-01-31 20:33:08 +02:00 · 2026-01-31 20:21:22 +02:00 · 2026-01-31 19:45:24 +02:00 · 2026-01-31 19:12:00 +02:00
28 changed files with 1712 additions and 129 deletions
--- a/cmd/relspec/scripts.go
+++ b/cmd/relspec/scripts.go
@@ -14,10 +14,11 @@ import (
 )

 var (
-	scriptsDir        string
-	scriptsConn       string
-	scriptsSchemaName string
-	scriptsDBName     string
+	scriptsDir          string
+	scriptsConn         string
+	scriptsSchemaName   string
+	scriptsDBName       string
+	scriptsIgnoreErrors bool
 )

 var scriptsCmd = &cobra.Command{
@@ -62,7 +63,7 @@ var scriptsExecuteCmd = &cobra.Command{
 	Long: `Execute SQL scripts from a directory against a PostgreSQL database.

 Scripts are executed in order: Priority (ascending), Sequence (ascending), Name (alphabetical).
-Execution stops immediately on the first error.
+By default, execution stops immediately on the first error. Use --ignore-errors to continue execution.

 The directory is scanned recursively for all subdirectories and files matching the patterns:
  {priority}_{sequence}_{name}.sql or .pgsql (underscore format)
@@ -86,7 +87,12 @@ Examples:

  # Execute with SSL disabled
  relspec scripts execute --dir ./sql \
-                          --conn "postgres://user:pass@localhost/db?sslmode=disable"`,
+                          --conn "postgres://user:pass@localhost/db?sslmode=disable"
+
+  # Continue executing even if errors occur
+  relspec scripts execute --dir ./migrations \
+                          --conn "postgres://localhost/mydb" \
+                          --ignore-errors`,
 	RunE: runScriptsExecute,
 }

@@ -105,6 +111,7 @@ func init() {
 	scriptsExecuteCmd.Flags().StringVar(&scriptsConn, "conn", "", "PostgreSQL connection string (required)")
 	scriptsExecuteCmd.Flags().StringVar(&scriptsSchemaName, "schema", "public", "Schema name (optional, default: public)")
 	scriptsExecuteCmd.Flags().StringVar(&scriptsDBName, "database", "database", "Database name (optional, default: database)")
+	scriptsExecuteCmd.Flags().BoolVar(&scriptsIgnoreErrors, "ignore-errors", false, "Continue executing scripts even if errors occur")

 	err = scriptsExecuteCmd.MarkFlagRequired("dir")
 	if err != nil {
@@ -250,17 +257,39 @@ func runScriptsExecute(cmd *cobra.Command, args []string) error {
 	writer := sqlexec.NewWriter(&writers.WriterOptions{
 		Metadata: map[string]any{
 			"connection_string": scriptsConn,
+			"ignore_errors":     scriptsIgnoreErrors,
 		},
 	})

 	if err := writer.WriteSchema(schema); err != nil {
 		fmt.Fprintf(os.Stderr, "\n")
-		return fmt.Errorf("execution failed: %w", err)
+		return fmt.Errorf("script execution failed: %w", err)
+	}
+
+	// Get execution results from writer metadata
+	totalCount := len(schema.Scripts)
+	successCount := totalCount
+	failedCount := 0
+
+	opts := writer.Options()
+	if total, exists := opts.Metadata["execution_total"].(int); exists {
+		totalCount = total
+	}
+	if success, exists := opts.Metadata["execution_success"].(int); exists {
+		successCount = success
+	}
+	if failed, exists := opts.Metadata["execution_failed"].(int); exists {
+		failedCount = failed
 	}

 	fmt.Fprintf(os.Stderr, "\n=== Execution Complete ===\n")
 	fmt.Fprintf(os.Stderr, "Completed at: %s\n", getCurrentTimestamp())
-	fmt.Fprintf(os.Stderr, "Successfully executed %d script(s)\n\n", len(schema.Scripts))
+	fmt.Fprintf(os.Stderr, "Total scripts: %d\n", totalCount)
+	fmt.Fprintf(os.Stderr, "Successful:    %d\n", successCount)
+	if failedCount > 0 {
+		fmt.Fprintf(os.Stderr, "Failed:        %d\n", failedCount)
+	}
+	fmt.Fprintf(os.Stderr, "\n")

 	return nil
 }
--- a/pkg/readers/dbml/reader.go
+++ b/pkg/readers/dbml/reader.go
@@ -128,6 +128,46 @@ func (r *Reader) readDirectoryDBML(dirPath string) (*models.Database, error) {
 	return db, nil
 }

+// splitIdentifier splits a dotted identifier while respecting quotes
+// Handles cases like: "schema.with.dots"."table"."column"
+func splitIdentifier(s string) []string {
+	var parts []string
+	var current strings.Builder
+	inQuote := false
+	quoteChar := byte(0)
+
+	for i := 0; i < len(s); i++ {
+		ch := s[i]
+
+		if !inQuote {
+			switch ch {
+			case '"', '\'':
+				inQuote = true
+				quoteChar = ch
+				current.WriteByte(ch)
+			case '.':
+				if current.Len() > 0 {
+					parts = append(parts, current.String())
+					current.Reset()
+				}
+			default:
+				current.WriteByte(ch)
+			}
+		} else {
+			current.WriteByte(ch)
+			if ch == quoteChar {
+				inQuote = false
+			}
+		}
+	}
+
+	if current.Len() > 0 {
+		parts = append(parts, current.String())
+	}
+
+	return parts
+}
+
 // stripQuotes removes surrounding quotes and comments from an identifier
 func stripQuotes(s string) string {
 	s = strings.TrimSpace(s)
@@ -409,7 +449,9 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 		// Parse Table definition
 		if matches := tableRegex.FindStringSubmatch(line); matches != nil {
 			tableName := matches[1]
-			parts := strings.Split(tableName, ".")
+			// Strip comments/notes before parsing to avoid dots in notes
+			tableName = strings.TrimSpace(regexp.MustCompile(`\s*\[.*?\]\s*`).ReplaceAllString(tableName, ""))
+			parts := splitIdentifier(tableName)

 			if len(parts) == 2 {
 				currentSchema = stripQuotes(parts[0])
@@ -562,7 +604,7 @@ func (r *Reader) parseColumn(line, tableName, schemaName string) (*models.Column
 				} else if attr == "unique" {
 					// Create a unique constraint
 					uniqueConstraint := models.InitConstraint(
-						fmt.Sprintf("uq_%s", columnName),
+						fmt.Sprintf("uq_%s_%s", tableName, columnName),
 						models.UniqueConstraint,
 					)
 					uniqueConstraint.Schema = schemaName
@@ -610,8 +652,8 @@ 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, "_"))
 					}
 				}
 			}
@@ -695,7 +737,11 @@ 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
@@ -755,10 +801,10 @@ 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(
@@ -814,7 +860,7 @@ func (r *Reader) parseTableRef(ref string) (schema, table string, columns []stri
 	}

 	// Parse schema, table, and optionally column
-	parts := strings.Split(strings.TrimSpace(ref), ".")
+	parts := splitIdentifier(strings.TrimSpace(ref))
 	if len(parts) == 3 {
 		// Format: "schema"."table"."column"
 		schema = stripQuotes(parts[0])
--- a/pkg/readers/dbml/reader_test.go
+++ b/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: uq_table_column
+	if _, exists := usersTable.Constraints["uq_users_email"]; !exists {
+		t.Error("Expected unique constraint 'uq_users_email' not found")
+		t.Logf("Available constraints: %v", getKeys(usersTable.Constraints))
+	}
+
+	if _, exists := postsTable.Constraints["uq_posts_slug"]; !exists {
+		t.Error("Expected unique constraint 'uq_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 {
--- a/pkg/writers/pgsql/migration_writer_test.go
+++ b/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")
+	}
+}
--- a/pkg/writers/pgsql/template_functions.go
+++ b/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
--- a/pkg/writers/pgsql/template_functions_test.go
+++ b/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",
--- a/pkg/writers/pgsql/templates.go
+++ b/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
--- a/pkg/writers/pgsql/templates/add_column.tmpl
+++ b/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}};
--- a/pkg/writers/pgsql/templates/add_column_with_check.tmpl
+++ b/pkg/writers/pgsql/templates/add_column_with_check.tmpl
@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND column_name = '{{.ColumnName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD COLUMN {{.ColumnDefinition}};
+  END IF;
+END;
+$$;
--- a/pkg/writers/pgsql/templates/alter_column_default.tmpl
+++ b/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 -}}
--- a/pkg/writers/pgsql/templates/alter_column_type.tmpl
+++ b/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}};
--- a/pkg/writers/pgsql/templates/comment_column.tmpl
+++ b/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}}';
--- a/pkg/writers/pgsql/templates/comment_table.tmpl
+++ b/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}}';
--- a/pkg/writers/pgsql/templates/create_check_constraint.tmpl
+++ b/pkg/writers/pgsql/templates/create_check_constraint.tmpl
@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} CHECK ({{.Expression}});
+  END IF;
+END;
+$$;
--- a/pkg/writers/pgsql/templates/create_foreign_key.tmpl
+++ b/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;
--- a/pkg/writers/pgsql/templates/create_foreign_key_with_check.tmpl
+++ b/pkg/writers/pgsql/templates/create_foreign_key_with_check.tmpl
@@ -0,0 +1,18 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+      ADD CONSTRAINT {{quote_ident .ConstraintName}}
+      FOREIGN KEY ({{.SourceColumns}})
+      REFERENCES {{quote_ident .TargetSchema}}.{{quote_ident .TargetTable}} ({{.TargetColumns}})
+      ON DELETE {{.OnDelete}}
+      ON UPDATE {{.OnUpdate}}{{if .Deferrable}}
+      DEFERRABLE{{end}};
+  END IF;
+END;
+$$;
--- a/pkg/writers/pgsql/templates/create_index.tmpl
+++ b/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}});
--- a/pkg/writers/pgsql/templates/create_primary_key.tmpl
+++ b/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;
 $$;
--- a/pkg/writers/pgsql/templates/create_primary_key_with_autogen_check.tmpl
+++ b/pkg/writers/pgsql/templates/create_primary_key_with_autogen_check.tmpl
@@ -0,0 +1,27 @@
+DO $$
+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;
+$$;
--- a/pkg/writers/pgsql/templates/create_sequence.tmpl
+++ b/pkg/writers/pgsql/templates/create_sequence.tmpl
@@ -0,0 +1,6 @@
+CREATE SEQUENCE IF NOT EXISTS {{quote_ident .SchemaName}}.{{quote_ident .SequenceName}}
+  INCREMENT {{.Increment}}
+  MINVALUE {{.MinValue}}
+  MAXVALUE {{.MaxValue}}
+  START {{.StartValue}}
+  CACHE {{.CacheSize}};
--- a/pkg/writers/pgsql/templates/create_table.tmpl
+++ b/pkg/writers/pgsql/templates/create_table.tmpl
@@ -1,7 +1,7 @@
-CREATE TABLE IF NOT EXISTS {{.SchemaName}}.{{.TableName}} (
+CREATE TABLE IF NOT EXISTS {{quote_ident .SchemaName}}.{{quote_ident .TableName}} (
 {{- range $i, $col := .Columns}}
 {{- if $i}},{{end}}
-  {{$col.Name}} {{$col.Type}}
+  {{quote_ident $col.Name}} {{$col.Type}}
 {{- if $col.Default}} DEFAULT {{$col.Default}}{{end}}
 {{- if $col.NotNull}} NOT NULL{{end}}
 {{- end}}
--- a/pkg/writers/pgsql/templates/create_unique_constraint.tmpl
+++ b/pkg/writers/pgsql/templates/create_unique_constraint.tmpl
@@ -0,0 +1,12 @@
+DO $$
+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;
+$$;
--- a/pkg/writers/pgsql/templates/drop_constraint.tmpl
+++ b/pkg/writers/pgsql/templates/drop_constraint.tmpl
@@ -1 +1 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}} DROP CONSTRAINT IF EXISTS {{.ConstraintName}};
+ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} DROP CONSTRAINT IF EXISTS {{quote_ident .ConstraintName}};
--- a/pkg/writers/pgsql/templates/drop_index.tmpl
+++ b/pkg/writers/pgsql/templates/drop_index.tmpl
@@ -1 +1 @@
-DROP INDEX IF EXISTS {{.SchemaName}}.{{.IndexName}} CASCADE;
+DROP INDEX IF EXISTS {{quote_ident .SchemaName}}.{{quote_ident .IndexName}} CASCADE;
--- a/pkg/writers/pgsql/templates/set_sequence_value.tmpl
+++ b/pkg/writers/pgsql/templates/set_sequence_value.tmpl
@@ -0,0 +1,19 @@
+DO $$
+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;
+$$;
--- a/pkg/writers/pgsql/writer.go
+++ b/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,
 	}
 }

@@ -168,6 +171,13 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 		statements = append(statements, stmts...)
 	}

+	// Phase 3.5: Add missing columns (for existing tables)
+	addColStmts, err := w.GenerateAddColumnStatements(schema)
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate add column statements: %w", err)
+	}
+	statements = append(statements, addColStmts...)
+
 	// Phase 4: Primary keys
 	for _, table := range schema.Tables {
 		// First check for explicit PrimaryKeyConstraint
@@ -179,27 +189,50 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 			}
 		}

+		var pkColumns []string
+		var pkName string
+
 		if pkConstraint != nil {
-			stmt := fmt.Sprintf("ALTER TABLE %s.%s ADD CONSTRAINT %s PRIMARY KEY (%s)",
-				schema.SQLName(), table.SQLName(), pkConstraint.Name, strings.Join(pkConstraint.Columns, ", "))
-			statements = append(statements, stmt)
+			pkColumns = pkConstraint.Columns
+			pkName = pkConstraint.Name
 		} else {
 			// No explicit constraint, check for columns with IsPrimaryKey = true
-			pkColumns := []string{}
+			pkCols := []string{}
 			for _, col := range table.Columns {
 				if col.IsPrimaryKey {
-					pkColumns = append(pkColumns, col.SQLName())
+					pkCols = append(pkCols, col.SQLName())
 				}
 			}
-			if len(pkColumns) > 0 {
+			if len(pkCols) > 0 {
 				// Sort for consistent output
-				sort.Strings(pkColumns)
-				pkName := fmt.Sprintf("pk_%s_%s", schema.SQLName(), table.SQLName())
-				stmt := fmt.Sprintf("ALTER TABLE %s.%s ADD CONSTRAINT %s PRIMARY KEY (%s)",
-					schema.SQLName(), table.SQLName(), pkName, strings.Join(pkColumns, ", "))
-				statements = append(statements, stmt)
+				sort.Strings(pkCols)
+				pkColumns = pkCols
+				pkName = fmt.Sprintf("pk_%s_%s", schema.SQLName(), table.SQLName())
 			}
 		}
+
+		if len(pkColumns) > 0 {
+			// Auto-generated primary key names to check for and drop
+			autoGenPKNames := []string{
+				fmt.Sprintf("%s_pkey", table.Name),
+				fmt.Sprintf("%s_%s_pkey", schema.Name, table.Name),
+			}
+
+			// 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)
+		}
 	}

 	// Phase 5: Indexes
@@ -243,7 +276,53 @@ 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)
+		}
+	}
+
+	// Phase 5.5: Unique constraints
+	for _, table := range schema.Tables {
+		for _, constraint := range table.Constraints {
+			if constraint.Type != models.UniqueConstraint {
+				continue
+			}
+
+			// 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)
 		}
 	}
@@ -270,12 +349,24 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				onUpdate = "NO ACTION"
 			}

-			stmt := fmt.Sprintf("ALTER TABLE %s.%s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s.%s(%s) ON DELETE %s ON UPDATE %s",
-				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)
 		}
 	}
@@ -300,6 +391,67 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 	return statements, nil
 }

+// GenerateAddColumnStatements generates ALTER TABLE ADD COLUMN statements for existing tables
+// This is useful for schema evolution when new columns are added to existing tables
+func (w *Writer) GenerateAddColumnStatements(schema *models.Schema) ([]string, error) {
+	statements := []string{}
+
+	statements = append(statements, fmt.Sprintf("-- Add missing columns for schema: %s", schema.Name))
+
+	for _, table := range schema.Tables {
+		// Sort columns by sequence or name for consistent output
+		columns := make([]*models.Column, 0, len(table.Columns))
+		for _, col := range table.Columns {
+			columns = append(columns, col)
+		}
+		sort.Slice(columns, func(i, j int) bool {
+			if columns[i].Sequence != columns[j].Sequence {
+				return columns[i].Sequence < columns[j].Sequence
+			}
+			return columns[i].Name < columns[j].Name
+		})
+
+		for _, col := range columns {
+			colDef := w.generateColumnDefinition(col)
+
+			// 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)
+		}
+	}
+
+	return statements, nil
+}
+
+// GenerateAddColumnsForDatabase generates ALTER TABLE ADD COLUMN statements for the entire database
+func (w *Writer) GenerateAddColumnsForDatabase(db *models.Database) ([]string, error) {
+	statements := []string{}
+
+	statements = append(statements, "-- Add missing columns to existing tables")
+	statements = append(statements, fmt.Sprintf("-- Database: %s", db.Name))
+	statements = append(statements, "-- Generated by RelSpec")
+
+	for _, schema := range db.Schemas {
+		schemaStatements, err := w.GenerateAddColumnStatements(schema)
+		if err != nil {
+			return nil, fmt.Errorf("failed to generate add column statements for schema %s: %w", schema.Name, err)
+		}
+		statements = append(statements, schemaStatements...)
+	}
+
+	return statements, nil
+}
+
 // generateCreateTableStatement generates CREATE TABLE statement
 func (w *Writer) generateCreateTableStatement(schema *models.Schema, table *models.Table) ([]string, error) {
 	statements := []string{}
@@ -322,7 +474,7 @@ func (w *Writer) generateCreateTableStatement(schema *models.Schema, table *mode
 		columnDefs = append(columnDefs, "  "+def)
 	}

-	stmt := fmt.Sprintf("CREATE TABLE %s.%s (\n%s\n)",
+	stmt := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s.%s (\n%s\n)",
 		schema.SQLName(), table.SQLName(), strings.Join(columnDefs, ",\n"))
 	statements = append(statements, stmt)

@@ -336,14 +488,25 @@ func (w *Writer) generateColumnDefinition(col *models.Column) string {
 	// Type with length/precision - convert to valid PostgreSQL type
 	baseType := pgsql.ConvertSQLType(col.Type)
 	typeStr := baseType
+
+	// Only add size specifiers for types that support them
 	if col.Length > 0 && col.Precision == 0 {
-		typeStr = fmt.Sprintf("%s(%d)", baseType, col.Length)
-	} else if col.Precision > 0 {
-		if col.Scale > 0 {
-			typeStr = fmt.Sprintf("%s(%d,%d)", baseType, col.Precision, col.Scale)
-		} else {
-			typeStr = fmt.Sprintf("%s(%d)", baseType, col.Precision)
+		if supportsLength(baseType) {
+			typeStr = fmt.Sprintf("%s(%d)", baseType, col.Length)
+		} else if isTextTypeWithoutLength(baseType) {
+			// Convert text with length to varchar
+			typeStr = fmt.Sprintf("varchar(%d)", col.Length)
 		}
+		// For types that don't support length (integer, bigint, etc.), ignore the length
+	} else if col.Precision > 0 {
+		if supportsPrecision(baseType) {
+			if col.Scale > 0 {
+				typeStr = fmt.Sprintf("%s(%d,%d)", baseType, col.Precision, col.Scale)
+			} else {
+				typeStr = fmt.Sprintf("%s(%d)", baseType, col.Precision)
+			}
+		}
+		// For types that don't support precision, ignore it
 	}
 	parts = append(parts, typeStr)

@@ -396,6 +559,11 @@ func (w *Writer) WriteSchema(schema *models.Schema) error {
 		return err
 	}

+	// Phase 3.5: Add missing columns (priority 120)
+	if err := w.writeAddColumns(schema); err != nil {
+		return err
+	}
+
 	// Phase 4: Create primary keys (priority 160)
 	if err := w.writePrimaryKeys(schema); err != nil {
 		return err
@@ -406,6 +574,16 @@ func (w *Writer) WriteSchema(schema *models.Schema) error {
 		return err
 	}

+	// Phase 5.5: Create unique constraints (priority 185)
+	if err := w.writeUniqueConstraints(schema); err != nil {
+		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
@@ -437,6 +615,44 @@ func (w *Writer) WriteTable(table *models.Table) error {
 	return w.WriteSchema(schema)
 }

+// WriteAddColumnStatements writes ALTER TABLE ADD COLUMN statements for a database
+// This is used for schema evolution/migration when new columns are added
+func (w *Writer) WriteAddColumnStatements(db *models.Database) error {
+	var writer io.Writer
+	var file *os.File
+	var err error
+
+	// Use existing writer if already set (for testing)
+	if w.writer != nil {
+		writer = w.writer
+	} else if w.options.OutputPath != "" {
+		// Determine output destination
+		file, err = os.Create(w.options.OutputPath)
+		if err != nil {
+			return fmt.Errorf("failed to create output file: %w", err)
+		}
+		defer file.Close()
+		writer = file
+	} else {
+		writer = os.Stdout
+	}
+
+	w.writer = writer
+
+	// Generate statements
+	statements, err := w.GenerateAddColumnsForDatabase(db)
+	if err != nil {
+		return err
+	}
+
+	// Write each statement
+	for _, stmt := range statements {
+		fmt.Fprintf(w.writer, "%s;\n\n", stmt)
+	}
+
+	return nil
+}
+
 // writeCreateSchema generates CREATE SCHEMA statement
 func (w *Writer) writeCreateSchema(schema *models.Schema) error {
 	if schema.Name == "public" {
@@ -465,13 +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
@@ -490,15 +716,8 @@ func (w *Writer) writeCreateTables(schema *models.Schema) error {
 		columnDefs := make([]string, 0, len(columns))

 		for _, col := range columns {
-			colDef := fmt.Sprintf("  %s %s", col.SQLName(), pgsql.ConvertSQLType(col.Type))
-
-			// Add default value if present
-			if col.Default != nil && col.Default != "" {
-				// Strip backticks - DBML uses them for SQL expressions but PostgreSQL doesn't
-				defaultVal := fmt.Sprintf("%v", col.Default)
-				colDef += fmt.Sprintf(" DEFAULT %s", stripBackticks(defaultVal))
-			}
-
+			// Use generateColumnDefinition to properly handle type, length, precision, and defaults
+			colDef := "  " + w.generateColumnDefinition(col)
 			columnDefs = append(columnDefs, colDef)
 		}

@@ -509,6 +728,36 @@ func (w *Writer) writeCreateTables(schema *models.Schema) error {
 	return nil
 }

+// writeAddColumns generates ALTER TABLE ADD COLUMN statements for missing columns
+func (w *Writer) writeAddColumns(schema *models.Schema) error {
+	fmt.Fprintf(w.writer, "-- Add missing columns for schema: %s\n", schema.Name)
+
+	for _, table := range schema.Tables {
+		// Sort columns by sequence or name for consistent output
+		columns := getSortedColumns(table.Columns)
+
+		for _, col := range columns {
+			colDef := w.generateColumnDefinition(col)
+
+			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")
+		}
+	}
+
+	return nil
+}
+
 // writePrimaryKeys generates ALTER TABLE statements for primary keys
 func (w *Writer) writePrimaryKeys(schema *models.Schema) error {
 	fmt.Fprintf(w.writer, "-- Primary keys for schema: %s\n", schema.Name)
@@ -550,18 +799,26 @@ func (w *Writer) writePrimaryKeys(schema *models.Schema) error {
 			continue
 		}

-		fmt.Fprintf(w.writer, "DO $$\nBEGIN\n")
-		fmt.Fprintf(w.writer, "  IF NOT EXISTS (\n")
-		fmt.Fprintf(w.writer, "    SELECT 1 FROM information_schema.table_constraints\n")
-		fmt.Fprintf(w.writer, "    WHERE table_schema = '%s'\n", schema.Name)
-		fmt.Fprintf(w.writer, "      AND table_name = '%s'\n", table.Name)
-		fmt.Fprintf(w.writer, "      AND constraint_name = '%s'\n", pkName)
-		fmt.Fprintf(w.writer, "  ) THEN\n")
-		fmt.Fprintf(w.writer, "    ALTER TABLE %s.%s\n", schema.SQLName(), table.SQLName())
-		fmt.Fprintf(w.writer, "      ADD CONSTRAINT %s PRIMARY KEY (%s);\n",
-			pkName, strings.Join(columnNames, ", "))
-		fmt.Fprintf(w.writer, "  END IF;\n")
-		fmt.Fprintf(w.writer, "END;\n$$;\n\n")
+		// Auto-generated primary key names to check for and drop
+		autoGenPKNames := []string{
+			fmt.Sprintf("%s_pkey", table.Name),
+			fmt.Sprintf("%s_%s_pkey", schema.Name, table.Name),
+		}
+
+		data := CreatePrimaryKeyWithAutoGenCheckData{
+			SchemaName:     schema.Name,
+			TableName:      table.Name,
+			ConstraintName: pkName,
+			AutoGenNames:   formatStringList(autoGenPKNames),
+			Columns:        strings.Join(columnNames, ", "),
+		}
+
+		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
@@ -644,6 +901,91 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 	return nil
 }

+// writeUniqueConstraints generates ALTER TABLE statements for unique constraints
+func (w *Writer) writeUniqueConstraints(schema *models.Schema) error {
+	fmt.Fprintf(w.writer, "-- Unique 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.UniqueConstraint {
+				constraintNames = append(constraintNames, name)
+			}
+		}
+		sort.Strings(constraintNames)
+
+		for _, name := range constraintNames {
+			constraint := table.Constraints[name]
+
+			// Build column list
+			columnExprs := make([]string, 0, len(constraint.Columns))
+			for _, colName := range constraint.Columns {
+				if col, ok := table.Columns[colName]; ok {
+					columnExprs = append(columnExprs, col.SQLName())
+				}
+			}
+
+			if len(columnExprs) == 0 {
+				continue
+			}
+
+			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)
+		}
+	}
+
+	return nil
+}
+
 // writeForeignKeys generates ALTER TABLE statements for foreign keys
 func (w *Writer) writeForeignKeys(schema *models.Schema) error {
 	fmt.Fprintf(w.writer, "-- Foreign keys for schema: %s\n", schema.Name)
@@ -711,13 +1053,6 @@ func (w *Writer) writeForeignKeys(schema *models.Schema) error {
 				onUpdate = strings.ToUpper(fkConstraint.OnUpdate)
 			}

-			fmt.Fprintf(w.writer, "ALTER TABLE %s.%s\n", schema.SQLName(), table.SQLName())
-			fmt.Fprintf(w.writer, "  DROP CONSTRAINT IF EXISTS %s;\n", fkName)
-			fmt.Fprintf(w.writer, "\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, ", "))
-
 			// Use constraint's referenced schema/table or relationship's ToSchema/ToTable
 			refSchema := fkConstraint.ReferencedSchema
 			if refSchema == "" {
@@ -728,11 +1063,103 @@ func (w *Writer) writeForeignKeys(schema *models.Schema) error {
 				refTable = rel.ToTable
 			}

-			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\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)
 		}
 	}

@@ -751,26 +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
@@ -844,6 +1264,44 @@ func isTextType(colType string) bool {
 	return false
 }

+// supportsLength checks if a PostgreSQL type supports length specification
+func supportsLength(colType string) bool {
+	lengthTypes := []string{"varchar", "character varying", "char", "character", "bit", "bit varying", "varbit"}
+	lowerType := strings.ToLower(colType)
+	for _, t := range lengthTypes {
+		if lowerType == t || strings.HasPrefix(lowerType, t+"(") {
+			return true
+		}
+	}
+	return false
+}
+
+// supportsPrecision checks if a PostgreSQL type supports precision/scale specification
+func supportsPrecision(colType string) bool {
+	precisionTypes := []string{"numeric", "decimal", "time", "timestamp", "timestamptz", "timestamp with time zone", "timestamp without time zone", "time with time zone", "time without time zone", "interval"}
+	lowerType := strings.ToLower(colType)
+	for _, t := range precisionTypes {
+		if lowerType == t || strings.HasPrefix(lowerType, t+"(") {
+			return true
+		}
+	}
+	return false
+}
+
+// isTextTypeWithoutLength checks if type is text (which should convert to varchar when length is specified)
+func isTextTypeWithoutLength(colType string) bool {
+	return strings.EqualFold(colType, "text")
+}
+
+// formatStringList formats a list of strings as a SQL-safe comma-separated quoted list
+func formatStringList(items []string) string {
+	quoted := make([]string, len(items))
+	for i, item := range items {
+		quoted[i] = fmt.Sprintf("'%s'", escapeQuote(item))
+	}
+	return strings.Join(quoted, ", ")
+}
+
 // extractOperatorClass extracts operator class from index comment/note
 // Looks for common operator classes like gin_trgm_ops, gist_trgm_ops, etc.
 func extractOperatorClass(comment string) string {
@@ -1086,3 +1544,9 @@ func truncateStatement(stmt string) string {
 func getCurrentTimestamp() string {
 	return time.Now().Format("2006-01-02 15:04:05")
 }
+
+// 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)
+}
--- a/pkg/writers/pgsql/writer_test.go
+++ b/pkg/writers/pgsql/writer_test.go
@@ -164,6 +164,296 @@ func TestWriteForeignKeys(t *testing.T) {
 	}
 }

+func TestWriteUniqueConstraints(t *testing.T) {
+	// Create a test database with unique constraints
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create table with unique constraints
+	table := models.InitTable("users", "public")
+
+	// Add columns
+	emailCol := models.InitColumn("email", "users", "public")
+	emailCol.Type = "varchar(255)"
+	emailCol.NotNull = true
+	table.Columns["email"] = emailCol
+
+	guidCol := models.InitColumn("guid", "users", "public")
+	guidCol.Type = "uuid"
+	guidCol.NotNull = true
+	table.Columns["guid"] = guidCol
+
+	// Add unique constraints
+	emailConstraint := &models.Constraint{
+		Name:    "uq_email",
+		Type:    models.UniqueConstraint,
+		Schema:  "public",
+		Table:   "users",
+		Columns: []string{"email"},
+	}
+	table.Constraints["uq_email"] = emailConstraint
+
+	guidConstraint := &models.Constraint{
+		Name:    "uq_guid",
+		Type:    models.UniqueConstraint,
+		Schema:  "public",
+		Table:   "users",
+		Columns: []string{"guid"},
+	}
+	table.Constraints["uq_guid"] = guidConstraint
+
+	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 unique constraints are present
+	if !strings.Contains(output, "-- Unique constraints for schema: public") {
+		t.Errorf("Output missing unique constraints header")
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT uq_email UNIQUE (email)") {
+		t.Errorf("Output missing uq_email unique constraint\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT uq_guid UNIQUE (guid)") {
+		t.Errorf("Output missing uq_guid unique constraint\nFull output:\n%s", output)
+	}
+}
+
+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")
@@ -305,3 +595,263 @@ func TestTypeConversion(t *testing.T) {
 		t.Errorf("Output missing 'smallint' type (converted from 'int16')\nFull output:\n%s", output)
 	}
 }
+
+func TestPrimaryKeyExistenceCheck(t *testing.T) {
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+	table := models.InitTable("products", "public")
+
+	idCol := models.InitColumn("id", "products", "public")
+	idCol.Type = "integer"
+	idCol.IsPrimaryKey = true
+	table.Columns["id"] = idCol
+
+	nameCol := models.InitColumn("name", "products", "public")
+	nameCol.Type = "text"
+	table.Columns["name"] = nameCol
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify our naming convention is used
+	if !strings.Contains(output, "pk_public_products") {
+		t.Errorf("Output missing expected primary key name 'pk_public_products'\nFull output:\n%s", output)
+	}
+
+	// Verify it drops auto-generated primary keys
+	if !strings.Contains(output, "products_pkey") || !strings.Contains(output, "DROP CONSTRAINT") {
+		t.Errorf("Output missing logic to drop auto-generated primary key\nFull output:\n%s", output)
+	}
+
+	// Verify it checks for our specific named constraint before adding it
+	if !strings.Contains(output, "constraint_name = 'pk_public_products'") {
+		t.Errorf("Output missing check for our named primary key constraint\nFull output:\n%s", output)
+	}
+}
+
+func TestColumnSizeSpecifiers(t *testing.T) {
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+	table := models.InitTable("test_sizes", "public")
+
+	// Integer with invalid size specifier - should ignore size
+	integerCol := models.InitColumn("int_col", "test_sizes", "public")
+	integerCol.Type = "integer"
+	integerCol.Length = 32
+	table.Columns["int_col"] = integerCol
+
+	// Bigint with invalid size specifier - should ignore size
+	bigintCol := models.InitColumn("bigint_col", "test_sizes", "public")
+	bigintCol.Type = "bigint"
+	bigintCol.Length = 64
+	table.Columns["bigint_col"] = bigintCol
+
+	// Smallint with invalid size specifier - should ignore size
+	smallintCol := models.InitColumn("smallint_col", "test_sizes", "public")
+	smallintCol.Type = "smallint"
+	smallintCol.Length = 16
+	table.Columns["smallint_col"] = smallintCol
+
+	// Text with length - should convert to varchar
+	textCol := models.InitColumn("text_col", "test_sizes", "public")
+	textCol.Type = "text"
+	textCol.Length = 100
+	table.Columns["text_col"] = textCol
+
+	// Varchar with length - should keep varchar with length
+	varcharCol := models.InitColumn("varchar_col", "test_sizes", "public")
+	varcharCol.Type = "varchar"
+	varcharCol.Length = 50
+	table.Columns["varchar_col"] = varcharCol
+
+	// Decimal with precision and scale - should keep them
+	decimalCol := models.InitColumn("decimal_col", "test_sizes", "public")
+	decimalCol.Type = "decimal"
+	decimalCol.Precision = 19
+	decimalCol.Scale = 4
+	table.Columns["decimal_col"] = decimalCol
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify invalid size specifiers are NOT present
+	invalidPatterns := []string{
+		"integer(32)",
+		"bigint(64)",
+		"smallint(16)",
+		"text(100)",
+	}
+	for _, pattern := range invalidPatterns {
+		if strings.Contains(output, pattern) {
+			t.Errorf("Output contains invalid pattern '%s' - PostgreSQL doesn't support this\nFull output:\n%s", pattern, output)
+		}
+	}
+
+	// Verify valid patterns ARE present
+	validPatterns := []string{
+		"integer",     // without size
+		"bigint",      // without size
+		"smallint",    // without size
+		"varchar(100)", // text converted to varchar with length
+		"varchar(50)",  // varchar with length
+		"decimal(19,4)", // decimal with precision and scale
+	}
+	for _, pattern := range validPatterns {
+		if !strings.Contains(output, pattern) {
+			t.Errorf("Output missing expected pattern '%s'\nFull output:\n%s", pattern, output)
+		}
+	}
+}
+
+func TestGenerateAddColumnStatements(t *testing.T) {
+	// Create a test database with tables that have new columns
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create a table with columns
+	table := models.InitTable("users", "public")
+
+	// Existing column
+	idCol := models.InitColumn("id", "users", "public")
+	idCol.Type = "integer"
+	idCol.NotNull = true
+	idCol.Sequence = 1
+	table.Columns["id"] = idCol
+
+	// New column to be added
+	emailCol := models.InitColumn("email", "users", "public")
+	emailCol.Type = "varchar"
+	emailCol.Length = 255
+	emailCol.NotNull = true
+	emailCol.Sequence = 2
+	table.Columns["email"] = emailCol
+
+	// New column with default
+	statusCol := models.InitColumn("status", "users", "public")
+	statusCol.Type = "text"
+	statusCol.Default = "active"
+	statusCol.Sequence = 3
+	table.Columns["status"] = statusCol
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+
+	// Generate ADD COLUMN statements
+	statements, err := writer.GenerateAddColumnsForDatabase(db)
+	if err != nil {
+		t.Fatalf("GenerateAddColumnsForDatabase failed: %v", err)
+	}
+
+	// Join all statements to verify content
+	output := strings.Join(statements, "\n")
+	t.Logf("Generated ADD COLUMN statements:\n%s", output)
+
+	// Verify expected elements
+	expectedStrings := []string{
+		"ALTER TABLE public.users ADD COLUMN id integer NOT NULL",
+		"ALTER TABLE public.users ADD COLUMN email varchar(255) NOT NULL",
+		"ALTER TABLE public.users ADD COLUMN status text DEFAULT 'active'",
+		"information_schema.columns",
+		"table_schema = 'public'",
+		"table_name = 'users'",
+		"column_name = 'id'",
+		"column_name = 'email'",
+		"column_name = 'status'",
+	}
+
+	for _, expected := range expectedStrings {
+		if !strings.Contains(output, expected) {
+			t.Errorf("Output missing expected string: %s\nFull output:\n%s", expected, output)
+		}
+	}
+
+	// Verify DO blocks are present for conditional adds
+	doBlockCount := strings.Count(output, "DO $$")
+	if doBlockCount < 3 {
+		t.Errorf("Expected at least 3 DO blocks (one per column), got %d", doBlockCount)
+	}
+
+	// Verify IF NOT EXISTS logic
+	ifNotExistsCount := strings.Count(output, "IF NOT EXISTS")
+	if ifNotExistsCount < 3 {
+		t.Errorf("Expected at least 3 IF NOT EXISTS checks (one per column), got %d", ifNotExistsCount)
+	}
+}
+
+func TestWriteAddColumnStatements(t *testing.T) {
+	// Create a test database
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create a table with a new column to be added
+	table := models.InitTable("products", "public")
+
+	idCol := models.InitColumn("id", "products", "public")
+	idCol.Type = "integer"
+	table.Columns["id"] = idCol
+
+	// New column with various properties
+	descCol := models.InitColumn("description", "products", "public")
+	descCol.Type = "text"
+	descCol.NotNull = false
+	table.Columns["description"] = descCol
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write ADD COLUMN statements
+	err := writer.WriteAddColumnStatements(db)
+	if err != nil {
+		t.Fatalf("WriteAddColumnStatements failed: %v", err)
+	}
+
+	output := buf.String()
+	t.Logf("Generated output:\n%s", output)
+
+	// Verify output contains expected elements
+	if !strings.Contains(output, "ALTER TABLE public.products ADD COLUMN id integer") {
+		t.Errorf("Output missing ADD COLUMN for id\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ALTER TABLE public.products ADD COLUMN description text") {
+		t.Errorf("Output missing ADD COLUMN for description\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "DO $$") {
+		t.Errorf("Output missing DO block\nFull output:\n%s", output)
+	}
+}
--- a/pkg/writers/sqlexec/writer.go
+++ b/pkg/writers/sqlexec/writer.go
@@ -23,6 +23,11 @@ func NewWriter(options *writers.WriterOptions) *Writer {
 	}
 }

+// Options returns the writer options (useful for reading execution results)
+func (w *Writer) Options() *writers.WriterOptions {
+	return w.options
+}
+
 // WriteDatabase executes all scripts from all schemas in the database
 func (w *Writer) WriteDatabase(db *models.Database) error {
 	if db == nil {
@@ -92,6 +97,22 @@ func (w *Writer) executeScripts(ctx context.Context, conn *pgx.Conn, scripts []*
 		return nil
 	}

+	// Check if we should ignore errors
+	ignoreErrors := false
+	if val, ok := w.options.Metadata["ignore_errors"].(bool); ok {
+		ignoreErrors = val
+	}
+
+	// Track failed scripts and execution counts
+	var failedScripts []struct {
+		name     string
+		priority int
+		sequence uint
+		err      error
+	}
+	successCount := 0
+	totalCount := 0
+
 	// Sort scripts by Priority (ascending), Sequence (ascending), then Name (ascending)
 	sortedScripts := make([]*models.Script, len(scripts))
 	copy(sortedScripts, scripts)
@@ -111,18 +132,49 @@ func (w *Writer) executeScripts(ctx context.Context, conn *pgx.Conn, scripts []*
 			continue
 		}

+		totalCount++
 		fmt.Printf("Executing script: %s (Priority=%d, Sequence=%d)\n",
 			script.Name, script.Priority, script.Sequence)

 		// Execute the SQL script
 		_, err := conn.Exec(ctx, script.SQL)
 		if err != nil {
-			return fmt.Errorf("failed to execute script %s (Priority=%d, Sequence=%d): %w",
+			if ignoreErrors {
+				fmt.Printf("⚠ Error executing %s: %v (continuing due to --ignore-errors)\n", script.Name, err)
+				failedScripts = append(failedScripts, struct {
+					name     string
+					priority int
+					sequence uint
+					err      error
+				}{
+					name:     script.Name,
+					priority: script.Priority,
+					sequence: script.Sequence,
+					err:      err,
+				})
+				continue
+			}
+			return fmt.Errorf("script %s (Priority=%d, Sequence=%d): %w",
 				script.Name, script.Priority, script.Sequence, err)
 		}

+		successCount++
 		fmt.Printf("✓ Successfully executed: %s\n", script.Name)
 	}

+	// Store execution results in metadata for caller
+	w.options.Metadata["execution_total"] = totalCount
+	w.options.Metadata["execution_success"] = successCount
+	w.options.Metadata["execution_failed"] = len(failedScripts)
+
+	// Print summary of failed scripts if any
+	if len(failedScripts) > 0 {
+		fmt.Printf("\n⚠ Failed Scripts Summary (%d failed):\n", len(failedScripts))
+		for i, failed := range failedScripts {
+			fmt.Printf("  %d. %s (Priority=%d, Sequence=%d)\n     Error: %v\n",
+				i+1, failed.name, failed.priority, failed.sequence, failed.err)
+		}
+	}
+
 	return nil
 }
Author	SHA1	Message	Date
Hein	165623bb1d	feat(pgsql): ✨ Add templates for constraints and sequences All checks were successful CI / Test (1.24) (push) Successful in -26m21s Details CI / Test (1.25) (push) Successful in -26m13s Details CI / Build (push) Successful in -26m39s Details CI / Lint (push) Successful in -26m29s Details Release / Build and Release (push) Successful in -26m28s Details Integration Tests / Integration Tests (push) Successful in -26m10s Details * Introduce new templates for creating unique, check, and foreign key constraints with existence checks. * Add templates for setting sequence values and creating sequences. * Refactor existing SQL generation logic to utilize new templates for better maintainability and readability. * Ensure identifiers are properly quoted to handle special characters and reserved keywords.	2026-01-31 21:04:43 +02:00
Hein	3c20c3c5d9	feat(writer): 🎉 Add support for check constraints in schema generation All checks were successful CI / Test (1.24) (push) Successful in -26m17s Details CI / Test (1.25) (push) Successful in -26m14s Details CI / Build (push) Successful in -26m41s Details CI / Lint (push) Successful in -26m32s Details Release / Build and Release (push) Successful in -26m31s Details Integration Tests / Integration Tests (push) Successful in -26m13s Details * Implement check constraints in the schema writer. * Generate SQL statements to add check constraints if they do not exist. * Add tests to verify correct generation of check constraints.	2026-01-31 20:42:19 +02:00
Hein	a54594e49b	feat(writer): 🎉 Add support for unique constraints in schema generation All checks were successful CI / Test (1.24) (push) Successful in -26m26s Details CI / Test (1.25) (push) Successful in -26m18s Details CI / Lint (push) Successful in -26m25s Details CI / Build (push) Successful in -26m35s Details Release / Build and Release (push) Successful in -26m29s Details Integration Tests / Integration Tests (push) Successful in -26m11s Details * Implement unique constraint handling in GenerateSchemaStatements * Add writeUniqueConstraints method for generating SQL statements * Create unit test for unique constraints in writer_test.go	2026-01-31 20:33:08 +02:00
Hein	cafe6a461f	feat(scripts): 🎉 Add --ignore-errors flag for script execution All checks were successful CI / Test (1.24) (push) Successful in -26m18s Details CI / Test (1.25) (push) Successful in -26m14s Details CI / Build (push) Successful in -26m38s Details CI / Lint (push) Successful in -26m30s Details Release / Build and Release (push) Successful in -26m27s Details Integration Tests / Integration Tests (push) Successful in -26m10s Details - Allow continued execution of scripts even if errors occur. - Update execution summary to include counts of successful and failed scripts. - Enhance error handling and reporting for better visibility.	2026-01-31 20:21:22 +02:00
Hein	abdb9b4c78	feat(dbml/reader): 🎉 Implement splitIdentifier function for parsing All checks were successful CI / Test (1.24) (push) Successful in -26m24s Details CI / Test (1.25) (push) Successful in -26m17s Details CI / Build (push) Successful in -26m44s Details CI / Lint (push) Successful in -26m33s Details Integration Tests / Integration Tests (push) Successful in -26m11s Details Release / Build and Release (push) Successful in -26m36s Details	2026-01-31 19:45:24 +02:00
Hein	e7a15c8e4f	feat(writer): 🎉 Implement add column statements for schema evolution All checks were successful CI / Test (1.24) (push) Successful in -26m24s Details CI / Test (1.25) (push) Successful in -26m14s Details CI / Lint (push) Successful in -26m30s Details CI / Build (push) Successful in -26m41s Details Release / Build and Release (push) Successful in -26m29s Details Integration Tests / Integration Tests (push) Successful in -26m13s Details * Add functionality to generate ALTER TABLE ADD COLUMN statements for existing tables. * Introduce tests for generating and writing add column statements. * Enhance schema evolution capabilities when new columns are added.	2026-01-31 19:12:00 +02:00
Hein	c36b5ede2b	feat(writer): 🎉 Enhance primary key handling and add tests All checks were successful CI / Test (1.24) (push) Successful in -26m18s Details CI / Test (1.25) (push) Successful in -26m11s Details CI / Build (push) Successful in -26m43s Details CI / Lint (push) Successful in -26m34s Details Release / Build and Release (push) Successful in -26m31s Details Integration Tests / Integration Tests (push) Successful in -26m20s Details * Implement checks for existing primary keys before adding new ones. * Drop auto-generated primary keys if they exist. * Add tests for primary key existence and column size specifiers. * Improve type conversion handling for PostgreSQL compatibility.	2026-01-31 18:59:32 +02:00