.

Bun and GORM struct tags now emit quoted defaults for string/date/time/UUID
columns (e.g. default:'disconnected') and unquoted defaults for numeric and
boolean columns (e.g. default:0, default:true). Function-call expressions
such as now() or gen_random_uuid() are never quoted regardless of type.

Adds QuoteDefaultValue(value, sqlType) helper in pkg/writers and updates
both type mappers and the bun writer tests accordingly.

pkg/readers/gorm/reader.go

@@ -676,19 +676,8 @@ func (r *Reader) extractTableFromGormTag(tag string) (tablename string, schemaNa
 
 // deriveTableName derives a table name from struct name
 func (r *Reader) deriveTableName(structName string) string {
-	// Remove "Model" prefix if present
+	// Remove "Model" prefix if present, use the name as-is without transformation
-	name := strings.TrimPrefix(structName, "Model")
+	return strings.TrimPrefix(structName, "Model")
-
-	// Convert PascalCase to snake_case
-	var result strings.Builder
-	for i, r := range name {
-		if i > 0 && r >= 'A' && r <= 'Z' {
-			result.WriteRune('_')
-		}
-		result.WriteRune(r)
-	}
-
-	return strings.ToLower(result.String())
 }
 
 // parseColumn parses a struct field into a Column model

pkg/readers/pgsql/queries.go

@@ -231,14 +231,13 @@ func (r *Reader) queryColumns(schemaName string) (map[string]map[string]*models.
 		}
 
 		column := models.InitColumn(columnName, tableName, schema)
-		column.Type = r.mapDataType(dataType, udtName)
-		column.NotNull = (isNullable == "NO")
-		column.Sequence = uint(ordinalPosition)
 
+		// Check if this is a serial type (has nextval default)
+		hasNextval := false
 		if columnDefault != nil {
-			// Parse default value - remove nextval for sequences
 			defaultVal := *columnDefault
 			if strings.HasPrefix(defaultVal, "nextval") {
+				hasNextval = true
 				column.AutoIncrement = true
 				column.Default = defaultVal
 			} else {
@@ -246,6 +245,11 @@ func (r *Reader) queryColumns(schemaName string) (map[string]map[string]*models.
 			}
 		}
 
+		// Map data type, preserving serial types when detected
+		column.Type = r.mapDataType(dataType, udtName, hasNextval)
+		column.NotNull = (isNullable == "NO")
+		column.Sequence = uint(ordinalPosition)
+
 		if description != nil {
 			column.Description = *description
 		}

pkg/readers/pgsql/reader.go

@@ -3,6 +3,7 @@ package pgsql
 import (
 	"context"
 	"fmt"
+	"strings"
 
 	"github.com/jackc/pgx/v5"
 
@@ -259,33 +260,46 @@ func (r *Reader) close() {
 }
 
 // mapDataType maps PostgreSQL data types to canonical types
-func (r *Reader) mapDataType(pgType, udtName string) string {
+func (r *Reader) mapDataType(pgType, udtName string, hasNextval bool) string {
+	// If the column has a nextval default, it's likely a serial type
+	// Map to the appropriate serial type instead of the base integer type
+	if hasNextval {
+		switch strings.ToLower(pgType) {
+		case "integer", "int", "int4":
+			return "serial"
+		case "bigint", "int8":
+			return "bigserial"
+		case "smallint", "int2":
+			return "smallserial"
+		}
+	}
+
 	// Map common PostgreSQL types
 	typeMap := map[string]string{
-		"integer":                     "int",
+		"integer":                     "integer",
-		"bigint":                      "int64",
+		"bigint":                      "bigint",
-		"smallint":                    "int16",
+		"smallint":                    "smallint",
-		"int":                         "int",
+		"int":                         "integer",
-		"int2":                        "int16",
+		"int2":                        "smallint",
-		"int4":                        "int",
+		"int4":                        "integer",
-		"int8":                        "int64",
+		"int8":                        "bigint",
-		"serial":                      "int",
+		"serial":                      "serial",
-		"bigserial":                   "int64",
+		"bigserial":                   "bigserial",
-		"smallserial":                 "int16",
+		"smallserial":                 "smallserial",
-		"numeric":                     "decimal",
+		"numeric":                     "numeric",
 		"decimal":                     "decimal",
-		"real":                        "float32",
+		"real":                        "real",
-		"double precision":            "float64",
+		"double precision":            "double precision",
-		"float4":                      "float32",
+		"float4":                      "real",
-		"float8":                      "float64",
+		"float8":                      "double precision",
-		"money":                       "decimal",
+		"money":                       "money",
-		"character varying":           "string",
+		"character varying":           "varchar",
-		"varchar":                     "string",
+		"varchar":                     "varchar",
-		"character":                   "string",
+		"character":                   "char",
-		"char":                        "string",
+		"char":                        "char",
-		"text":                        "string",
+		"text":                        "text",
-		"boolean":                     "bool",
+		"boolean":                     "boolean",
-		"bool":                        "bool",
+		"bool":                        "boolean",
 		"date":                        "date",
 		"time":                        "time",
 		"time without time zone":      "time",

pkg/readers/pgsql/reader_test.go

@@ -177,20 +177,20 @@ func TestMapDataType(t *testing.T) {
 		udtName  string
 		expected string
 	}{
-		{"integer", "int4", "int"},
+		{"integer", "int4", "integer"},
-		{"bigint", "int8", "int64"},
+		{"bigint", "int8", "bigint"},
-		{"smallint", "int2", "int16"},
+		{"smallint", "int2", "smallint"},
-		{"character varying", "varchar", "string"},
+		{"character varying", "varchar", "varchar"},
-		{"text", "text", "string"},
+		{"text", "text", "text"},
-		{"boolean", "bool", "bool"},
+		{"boolean", "bool", "boolean"},
 		{"timestamp without time zone", "timestamp", "timestamp"},
 		{"timestamp with time zone", "timestamptz", "timestamptz"},
 		{"json", "json", "json"},
 		{"jsonb", "jsonb", "jsonb"},
 		{"uuid", "uuid", "uuid"},
-		{"numeric", "numeric", "decimal"},
+		{"numeric", "numeric", "numeric"},
-		{"real", "float4", "float32"},
+		{"real", "float4", "real"},
-		{"double precision", "float8", "float64"},
+		{"double precision", "float8", "double precision"},
 		{"date", "date", "date"},
 		{"time without time zone", "time", "time"},
 		{"bytea", "bytea", "bytea"},
@@ -199,12 +199,31 @@ func TestMapDataType(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.pgType, func(t *testing.T) {
-			result := reader.mapDataType(tt.pgType, tt.udtName)
+			result := reader.mapDataType(tt.pgType, tt.udtName, false)
 			if result != tt.expected {
 				t.Errorf("mapDataType(%s, %s) = %s, expected %s", tt.pgType, tt.udtName, result, tt.expected)
 			}
 		})
 	}
+
+	// Test serial type detection with hasNextval=true
+	serialTests := []struct {
+		pgType   string
+		expected string
+	}{
+		{"integer", "serial"},
+		{"bigint", "bigserial"},
+		{"smallint", "smallserial"},
+	}
+
+	for _, tt := range serialTests {
+		t.Run(tt.pgType+"_with_nextval", func(t *testing.T) {
+			result := reader.mapDataType(tt.pgType, "", true)
+			if result != tt.expected {
+				t.Errorf("mapDataType(%s, '', true) = %s, expected %s", tt.pgType, result, tt.expected)
+			}
+		})
+	}
 }
 
 func TestParseIndexDefinition(t *testing.T) {

pkg/writers/bun/type_mapper.go

@@ -62,6 +62,17 @@ func (tm *TypeMapper) isSimpleType(sqlType string) bool {
 	return simpleTypes[sqlType]
 }
 
+// isSerialType checks if a SQL type is a serial type (auto-incrementing)
+func (tm *TypeMapper) isSerialType(sqlType string) bool {
+	baseType := tm.extractBaseType(sqlType)
+	serialTypes := map[string]bool{
+		"serial":      true,
+		"bigserial":   true,
+		"smallserial": true,
+	}
+	return serialTypes[baseType]
+}
+
 // baseGoType returns the base Go type for a SQL type (not null, simple types only)
 func (tm *TypeMapper) baseGoType(sqlType string) string {
 	typeMap := map[string]string{
@@ -122,10 +133,10 @@ func (tm *TypeMapper) bunGoType(sqlType string) string {
 		"decimal":          tm.sqlTypesAlias + ".SqlFloat64",
 
 		// Date/Time types
-		"timestamp":                   tm.sqlTypesAlias + ".SqlTime",
+		"timestamp":                   tm.sqlTypesAlias + ".SqlTimeStamp",
-		"timestamp without time zone": tm.sqlTypesAlias + ".SqlTime",
+		"timestamp without time zone": tm.sqlTypesAlias + ".SqlTimeStamp",
-		"timestamp with time zone":    tm.sqlTypesAlias + ".SqlTime",
+		"timestamp with time zone":    tm.sqlTypesAlias + ".SqlTimeStamp",
-		"timestamptz":                 tm.sqlTypesAlias + ".SqlTime",
+		"timestamptz":                 tm.sqlTypesAlias + ".SqlTimeStamp",
 		"date":                        tm.sqlTypesAlias + ".SqlDate",
 		"time":                        tm.sqlTypesAlias + ".SqlTime",
 		"time without time zone":      tm.sqlTypesAlias + ".SqlTime",
@@ -190,10 +201,15 @@ func (tm *TypeMapper) BuildBunTag(column *models.Column, table *models.Table) st
 		parts = append(parts, "pk")
 	}
 
+	// Auto increment (for serial types or explicit auto_increment)
+	if column.AutoIncrement || tm.isSerialType(column.Type) {
+		parts = append(parts, "autoincrement")
+	}
+
 	// Default value
 	if column.Default != nil {
-		// Sanitize default value to remove backticks
+		// Sanitize default value to remove backticks, then quote based on column type
-		safeDefault := writers.SanitizeStructTagValue(fmt.Sprintf("%v", column.Default))
+		safeDefault := writers.QuoteDefaultValue(writers.SanitizeStructTagValue(fmt.Sprintf("%v", column.Default)), column.Type)
 		parts = append(parts, fmt.Sprintf("default:%s", safeDefault))
 	}
 

pkg/writers/bun/writer_test.go

@@ -90,8 +90,8 @@ func TestWriter_WriteTable(t *testing.T) {
 	}
 
 	// Verify Bun-specific elements
-	if !strings.Contains(generated, "bun:\"id,type:bigint,pk,") {
+	if !strings.Contains(generated, "bun:\"id,type:bigint,pk,autoincrement,") {
-		t.Errorf("Missing Bun-style primary key tag")
+		t.Errorf("Missing Bun-style primary key tag with autoincrement")
 	}
 }
 
@@ -567,8 +567,8 @@ func TestTypeMapper_SQLTypeToGoType_Bun(t *testing.T) {
 		{"bigint", false, "resolvespec_common.SqlInt64"},
 		{"varchar", true, "resolvespec_common.SqlString"}, // Bun uses sql types even for NOT NULL strings
 		{"varchar", false, "resolvespec_common.SqlString"},
-		{"timestamp", true, "resolvespec_common.SqlTime"},
+		{"timestamp", true, "resolvespec_common.SqlTimeStamp"},
-		{"timestamp", false, "resolvespec_common.SqlTime"},
+		{"timestamp", false, "resolvespec_common.SqlTimeStamp"},
 		{"date", false, "resolvespec_common.SqlDate"},
 		{"boolean", true, "bool"},
 		{"boolean", false, "resolvespec_common.SqlBool"},
@@ -615,14 +615,75 @@ func TestTypeMapper_BuildBunTag(t *testing.T) {
 			want: []string{"email,", "type:varchar(255),", "nullzero,"},
 		},
 		{
-			name: "with default",
+			name: "with default string",
 			column: &models.Column{
 				Name:    "status",
 				Type:    "text",
 				NotNull: true,
 				Default: "active",
 			},
-			want: []string{"status,", "type:text,", "default:active,"},
+			want: []string{"status,", "type:text,", "default:'active',"},
+		},
+		{
+			name: "with default integer",
+			column: &models.Column{
+				Name:    "retries",
+				Type:    "integer",
+				NotNull: true,
+				Default: "0",
+			},
+			want: []string{"retries,", "type:integer,", "default:0,"},
+		},
+		{
+			name: "with default boolean",
+			column: &models.Column{
+				Name:    "active",
+				Type:    "boolean",
+				NotNull: true,
+				Default: "true",
+			},
+			want: []string{"active,", "type:boolean,", "default:true,"},
+		},
+		{
+			name: "with default function call",
+			column: &models.Column{
+				Name:    "created_at",
+				Type:    "timestamp",
+				NotNull: true,
+				Default: "now()",
+			},
+			want: []string{"created_at,", "type:timestamp,", "default:now(),"},
+		},
+		{
+			name: "auto increment with AutoIncrement flag",
+			column: &models.Column{
+				Name:          "id",
+				Type:          "bigint",
+				NotNull:       true,
+				IsPrimaryKey:  true,
+				AutoIncrement: true,
+			},
+			want: []string{"id,", "type:bigint,", "pk,", "autoincrement,"},
+		},
+		{
+			name: "serial type (auto-increment)",
+			column: &models.Column{
+				Name:         "id",
+				Type:         "serial",
+				NotNull:      true,
+				IsPrimaryKey: true,
+			},
+			want: []string{"id,", "type:serial,", "pk,", "autoincrement,"},
+		},
+		{
+			name: "bigserial type (auto-increment)",
+			column: &models.Column{
+				Name:         "id",
+				Type:         "bigserial",
+				NotNull:      true,
+				IsPrimaryKey: true,
+			},
+			want: []string{"id,", "type:bigserial,", "pk,", "autoincrement,"},
 		},
 	}
 

pkg/writers/gorm/type_mapper.go

@@ -158,10 +158,10 @@ func (tm *TypeMapper) nullableGoType(sqlType string) string {
 		"decimal":          tm.sqlTypesAlias + ".SqlFloat64",
 
 		// Date/Time types
-		"timestamp":                   tm.sqlTypesAlias + ".SqlTime",
+		"timestamp":                   tm.sqlTypesAlias + ".SqlTimeStamp",
-		"timestamp without time zone": tm.sqlTypesAlias + ".SqlTime",
+		"timestamp without time zone": tm.sqlTypesAlias + ".SqlTimeStamp",
-		"timestamp with time zone":    tm.sqlTypesAlias + ".SqlTime",
+		"timestamp with time zone":    tm.sqlTypesAlias + ".SqlTimeStamp",
-		"timestamptz":                 tm.sqlTypesAlias + ".SqlTime",
+		"timestamptz":                 tm.sqlTypesAlias + ".SqlTimeStamp",
 		"date":                        tm.sqlTypesAlias + ".SqlDate",
 		"time":                        tm.sqlTypesAlias + ".SqlTime",
 		"time without time zone":      tm.sqlTypesAlias + ".SqlTime",
@@ -238,8 +238,8 @@ func (tm *TypeMapper) BuildGormTag(column *models.Column, table *models.Table) s
 
 	// Default value
 	if column.Default != nil {
-		// Sanitize default value to remove backticks
+		// Sanitize default value to remove backticks, then quote based on column type
-		safeDefault := writers.SanitizeStructTagValue(fmt.Sprintf("%v", column.Default))
+		safeDefault := writers.QuoteDefaultValue(writers.SanitizeStructTagValue(fmt.Sprintf("%v", column.Default)), column.Type)
 		parts = append(parts, fmt.Sprintf("default:%s", safeDefault))
 	}
 

pkg/writers/gorm/writer_test.go

@@ -655,7 +655,7 @@ func TestTypeMapper_SQLTypeToGoType(t *testing.T) {
 		{"varchar", true, "string"},
 		{"varchar", false, "sql_types.SqlString"},
 		{"timestamp", true, "time.Time"},
-		{"timestamp", false, "sql_types.SqlTime"},
+		{"timestamp", false, "sql_types.SqlTimeStamp"},
 		{"boolean", true, "bool"},
 		{"boolean", false, "sql_types.SqlBool"},
 	}

pkg/writers/writer.go

@@ -81,6 +81,64 @@ func SanitizeFilename(name string) string {
 	return name
 }
 
+// QuoteDefaultValue wraps a sanitized default value in single quotes when the SQL
+// column type requires it (strings, dates, times, UUIDs, enums). Numeric types
+// (integers, floats, serials) and boolean types are left unquoted. Function-call
+// expressions such as now() or gen_random_uuid() are always left unquoted regardless
+// of type, because they contain parentheses.
+//
+// Examples (varchar):   "disconnected" → "'disconnected'"
+// Examples (boolean):   "true"         → "true"
+// Examples (bigint):    "0"            → "0"
+// Examples (timestamp): "now()"        → "now()"   (function call – never quoted)
+func QuoteDefaultValue(value, sqlType string) string {
+	// Function calls are never quoted regardless of column type.
+	if strings.Contains(value, "(") || strings.Contains(value, ")") {
+		return value
+	}
+
+	// Normalise the SQL type: lowercase, strip length/precision suffix.
+	baseType := strings.ToLower(strings.TrimSpace(sqlType))
+	if idx := strings.Index(baseType, "("); idx > 0 {
+		baseType = baseType[:idx]
+	}
+
+	// Types whose default values must NOT be quoted.
+	unquotedTypes := map[string]bool{
+		// Integer types
+		"integer":     true,
+		"int":         true,
+		"int2":        true,
+		"int4":        true,
+		"int8":        true,
+		"smallint":    true,
+		"bigint":      true,
+		"serial":      true,
+		"smallserial": true,
+		"bigserial":   true,
+		// Float / numeric types
+		"real":             true,
+		"float":            true,
+		"float4":           true,
+		"float8":           true,
+		"double precision": true,
+		"numeric":          true,
+		"decimal":          true,
+		"money":            true,
+		// Boolean
+		"boolean": true,
+		"bool":    true,
+	}
+
+	if unquotedTypes[baseType] {
+		return value
+	}
+
+	// Everything else (text, varchar, char, uuid, date, time, timestamp, json, …)
+	// is treated as a quoted literal.
+	return "'" + value + "'"
+}
+
 // SanitizeStructTagValue sanitizes a value to be safely used inside Go struct tags.
 // Go struct tags are delimited by backticks, so any backtick in the value would break the syntax.
 // This function: