feat(relations): 🎉 add flatten schema option for output

* Introduce `--flatten-schema` flag to convert, merge, and split commands.
* Modify database writing functions to support flattened schema names.
* Update template functions to handle schema.table naming convention.
* Enhance PostgreSQL writer to utilize flattened schema in generated SQL.
* Update tests to ensure compatibility with new flattening feature.
* Dependencies updated for improved functionality.

cmd/relspec/convert.go

@@ -45,6 +45,7 @@ var (
 	convertTargetPath    string
 	convertPackageName   string
 	convertSchemaFilter  string
+	convertFlattenSchema bool
 )
 
 var convertCmd = &cobra.Command{
@@ -148,6 +149,7 @@ func init() {
 	convertCmd.Flags().StringVar(&convertTargetPath, "to-path", "", "Target output path (file or directory)")
 	convertCmd.Flags().StringVar(&convertPackageName, "package", "", "Package name (for code generation formats like gorm/bun)")
 	convertCmd.Flags().StringVar(&convertSchemaFilter, "schema", "", "Filter to a specific schema by name (required for formats like dctx that only support single schemas)")
+	convertCmd.Flags().BoolVar(&convertFlattenSchema, "flatten-schema", false, "Flatten schema.table names to schema_table (useful for databases like SQLite that do not support schemas)")
 
 	err := convertCmd.MarkFlagRequired("from")
 	if err != nil {
@@ -202,7 +204,7 @@ func runConvert(cmd *cobra.Command, args []string) error {
 		fmt.Fprintf(os.Stderr, "      Schema: %s\n", convertSchemaFilter)
 	}
 
-	if err := writeDatabase(db, convertTargetType, convertTargetPath, convertPackageName, convertSchemaFilter); err != nil {
+	if err := writeDatabase(db, convertTargetType, convertTargetPath, convertPackageName, convertSchemaFilter, convertFlattenSchema); err != nil {
 		return fmt.Errorf("failed to write target: %w", err)
 	}
 
@@ -301,12 +303,13 @@ func readDatabaseForConvert(dbType, filePath, connString string) (*models.Databa
 	return db, nil
 }
 
-func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string) error {
+func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string, flattenSchema bool) error {
 	var writer writers.Writer
 
 	writerOpts := &writers.WriterOptions{
 		OutputPath:    outputPath,
 		PackageName:   packageName,
+		FlattenSchema: flattenSchema,
 	}
 
 	switch strings.ToLower(dbType) {

cmd/relspec/merge.go

@@ -56,6 +56,7 @@ var (
 	mergeSkipTables    string // Comma-separated table names to skip
 	mergeVerbose       bool
 	mergeReportPath    string // Path to write merge report
+	mergeFlattenSchema bool
 )
 
 var mergeCmd = &cobra.Command{
@@ -123,6 +124,7 @@ func init() {
 	mergeCmd.Flags().StringVar(&mergeSkipTables, "skip-tables", "", "Comma-separated list of table names to skip during merge")
 	mergeCmd.Flags().BoolVar(&mergeVerbose, "verbose", false, "Show verbose output")
 	mergeCmd.Flags().StringVar(&mergeReportPath, "merge-report", "", "Path to write merge report (JSON format)")
+	mergeCmd.Flags().BoolVar(&mergeFlattenSchema, "flatten-schema", false, "Flatten schema.table names to schema_table (useful for databases like SQLite that do not support schemas)")
 }
 
 func runMerge(cmd *cobra.Command, args []string) error {
@@ -237,7 +239,7 @@ func runMerge(cmd *cobra.Command, args []string) error {
 		fmt.Fprintf(os.Stderr, "      Path:   %s\n", mergeOutputPath)
 	}
 
-	err = writeDatabaseForMerge(mergeOutputType, mergeOutputPath, mergeOutputConn, targetDB, "Output")
+	err = writeDatabaseForMerge(mergeOutputType, mergeOutputPath, mergeOutputConn, targetDB, "Output", mergeFlattenSchema)
 	if err != nil {
 		return fmt.Errorf("failed to write output: %w", err)
 	}
@@ -324,7 +326,7 @@ func readDatabaseForMerge(dbType, filePath, connString, label string) (*models.D
 	return db, nil
 }
 
-func writeDatabaseForMerge(dbType, filePath, connString string, db *models.Database, label string) error {
+func writeDatabaseForMerge(dbType, filePath, connString string, db *models.Database, label string, flattenSchema bool) error {
 	var writer writers.Writer
 
 	switch strings.ToLower(dbType) {
@@ -332,59 +334,59 @@ func writeDatabaseForMerge(dbType, filePath, connString string, db *models.Datab
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for DBML format", label)
 		}
-		writer = wdbml.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdbml.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "dctx":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for DCTX format", label)
 		}
-		writer = wdctx.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdctx.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "drawdb":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for DrawDB format", label)
 		}
-		writer = wdrawdb.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdrawdb.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "graphql":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for GraphQL format", label)
 		}
-		writer = wgraphql.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wgraphql.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "json":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for JSON format", label)
 		}
-		writer = wjson.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wjson.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "yaml":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for YAML format", label)
 		}
-		writer = wyaml.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wyaml.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "gorm":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for GORM format", label)
 		}
-		writer = wgorm.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wgorm.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "bun":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for Bun format", label)
 		}
-		writer = wbun.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wbun.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "drizzle":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for Drizzle format", label)
 		}
-		writer = wdrizzle.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdrizzle.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "prisma":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for Prisma format", label)
 		}
-		writer = wprisma.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wprisma.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "typeorm":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for TypeORM format", label)
 		}
-		writer = wtypeorm.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wtypeorm.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "pgsql":
-		writerOpts := &writers.WriterOptions{OutputPath: filePath}
+		writerOpts := &writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema}
 		if connString != "" {
 			writerOpts.Metadata = map[string]interface{}{
 				"connection_string": connString,

cmd/relspec/split.go

@@ -184,6 +184,7 @@ func runSplit(cmd *cobra.Command, args []string) error {
 		splitTargetPath,
 		splitPackageName,
 		"",    // no schema filter for split
+		false, // no flatten-schema for split
 	)
 	if err != nil {
 		return fmt.Errorf("failed to write output: %w", err)

pkg/writers/bun/template_data.go

@@ -106,11 +106,8 @@ func (td *TemplateData) FinalizeImports() {
 }
 
 // NewModelData creates a new ModelData from a models.Table
-func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper) *ModelData {
+func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper, flattenSchema bool) *ModelData {
-	tableName := table.Name
+	tableName := writers.QualifiedTableName(schema, table.Name, flattenSchema)
-	if schema != "" {
-		tableName = schema + "." + table.Name
-	}
 
 	// Generate model name: Model + Schema + Table (all PascalCase)
 	singularTable := Singularize(table.Name)

pkg/writers/bun/writer.go

@@ -86,7 +86,7 @@ func (w *Writer) writeSingleFile(db *models.Database) error {
 	// Collect all models
 	for _, schema := range db.Schemas {
 		for _, table := range schema.Tables {
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)
@@ -181,7 +181,7 @@ func (w *Writer) writeMultiFile(db *models.Database) error {
 			templateData.AddImport(fmt.Sprintf("resolvespec_common \"%s\"", w.typeMapper.GetSQLTypesImport()))
 
 			// Create model data
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)

pkg/writers/gorm/template_data.go

@@ -105,11 +105,8 @@ func (td *TemplateData) FinalizeImports() {
 }
 
 // NewModelData creates a new ModelData from a models.Table
-func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper) *ModelData {
+func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper, flattenSchema bool) *ModelData {
-	tableName := table.Name
+	tableName := writers.QualifiedTableName(schema, table.Name, flattenSchema)
-	if schema != "" {
-		tableName = schema + "." + table.Name
-	}
 
 	// Generate model name: Model + Schema + Table (all PascalCase)
 	singularTable := Singularize(table.Name)

pkg/writers/gorm/writer.go

@@ -83,7 +83,7 @@ func (w *Writer) writeSingleFile(db *models.Database) error {
 	// Collect all models
 	for _, schema := range db.Schemas {
 		for _, table := range schema.Tables {
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)
@@ -175,7 +175,7 @@ func (w *Writer) writeMultiFile(db *models.Database) error {
 			templateData.AddImport(fmt.Sprintf("sql_types \"%s\"", w.typeMapper.GetSQLTypesImport()))
 
 			// Create model data
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)

pkg/writers/pgsql/migration_writer.go

@@ -31,7 +31,7 @@ type MigrationWriter struct {
 
 // NewMigrationWriter creates a new templated migration writer
 func NewMigrationWriter(options *writers.WriterOptions) (*MigrationWriter, error) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(options.FlattenSchema)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create template executor: %w", err)
 	}

pkg/writers/pgsql/migration_writer_test.go

@@ -137,7 +137,7 @@ func TestWriteMigration_WithAudit(t *testing.T) {
 }
 
 func TestTemplateExecutor_CreateTable(t *testing.T) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(false)
 	if err != nil {
 		t.Fatalf("Failed to create executor: %v", err)
 	}
@@ -170,7 +170,7 @@ func TestTemplateExecutor_CreateTable(t *testing.T) {
 }
 
 func TestTemplateExecutor_AuditFunction(t *testing.T) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(false)
 	if err != nil {
 		t.Fatalf("Failed to create executor: %v", err)
 	}

pkg/writers/pgsql/template_functions_test.go

@@ -314,7 +314,7 @@ func TestFormatType(t *testing.T) {
 
 // Test that template functions work in actual templates
 func TestTemplateFunctionsInTemplate(t *testing.T) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(false)
 	if err != nil {
 		t.Fatalf("Failed to create executor: %v", err)
 	}

pkg/writers/pgsql/templates.go

@@ -18,14 +18,39 @@ type TemplateExecutor struct {
 	templates *template.Template
 }
 
-// NewTemplateExecutor creates a new template executor
+// NewTemplateExecutor creates a new template executor.
-func NewTemplateExecutor() (*TemplateExecutor, error) {
+// flattenSchema controls whether schema.table identifiers use dot or underscore separation.
+func NewTemplateExecutor(flattenSchema bool) (*TemplateExecutor, error) {
 	// Create template with custom functions
 	funcMap := make(template.FuncMap)
 	for k, v := range TemplateFunctions() {
 		funcMap[k] = v
 	}
 
+	// qual_table returns a quoted, schema-qualified identifier.
+	// With flatten=false: "schema"."table" (or unquoted equivalents).
+	// With flatten=true:  "schema_table".
+	funcMap["qual_table"] = func(schema, name string) string {
+		if schema == "" {
+			return quoteIdent(name)
+		}
+		if flattenSchema {
+			return quoteIdent(schema + "_" + name)
+		}
+		return quoteIdent(schema) + "." + quoteIdent(name)
+	}
+
+	// qual_table_raw is the same as qual_table but without identifier quoting.
+	funcMap["qual_table_raw"] = func(schema, name string) string {
+		if schema == "" {
+			return name
+		}
+		if flattenSchema {
+			return schema + "_" + name
+		}
+		return schema + "." + name
+	}
+
 	tmpl, err := template.New("").Funcs(funcMap).ParseFS(templateFS, "templates/*.tmpl")
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse templates: %w", err)

pkg/writers/pgsql/templates/add_column.tmpl

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

pkg/writers/pgsql/templates/add_column_with_check.tmpl

@@ -6,7 +6,7 @@ BEGIN
       AND table_name = '{{.TableName}}'
       AND column_name = '{{.ColumnName}}'
   ) THEN
-    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD COLUMN {{.ColumnDefinition}};
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD COLUMN {{.ColumnDefinition}};
   END IF;
 END;
 $$;

pkg/writers/pgsql/templates/alter_column_default.tmpl

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

pkg/writers/pgsql/templates/alter_column_type.tmpl

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

pkg/writers/pgsql/templates/audit_function.tmpl

@@ -1,4 +1,4 @@
-CREATE OR REPLACE FUNCTION {{.SchemaName}}.{{.FunctionName}}()
+CREATE OR REPLACE FUNCTION {{qual_table_raw .SchemaName .FunctionName}}()
 RETURNS trigger AS
 $body$
 DECLARE
@@ -81,4 +81,4 @@ LANGUAGE plpgsql
 VOLATILE
 SECURITY DEFINER;
 
-COMMENT ON FUNCTION {{.SchemaName}}.{{.FunctionName}}() IS 'Audit trigger function for table {{.SchemaName}}.{{.TableName}}';
+COMMENT ON FUNCTION {{qual_table_raw .SchemaName .FunctionName}}() IS 'Audit trigger function for table {{qual_table_raw .SchemaName .TableName}}';

pkg/writers/pgsql/templates/audit_trigger.tmpl

@@ -4,13 +4,13 @@ BEGIN
         SELECT 1
         FROM pg_trigger
         WHERE tgname = '{{.TriggerName}}'
-        AND tgrelid = '{{.SchemaName}}.{{.TableName}}'::regclass
+        AND tgrelid = '{{qual_table_raw .SchemaName .TableName}}'::regclass
     ) THEN
         CREATE TRIGGER {{.TriggerName}}
         AFTER {{.Events}}
-        ON {{.SchemaName}}.{{.TableName}}
+        ON {{qual_table_raw .SchemaName .TableName}}
         FOR EACH ROW
-        EXECUTE FUNCTION {{.SchemaName}}.{{.FunctionName}}();
+        EXECUTE FUNCTION {{qual_table_raw .SchemaName .FunctionName}}();
     END IF;
 END;
 $$;

pkg/writers/pgsql/templates/base_constraint.tmpl

@@ -1,6 +1,6 @@
 {{/* Base constraint template */}}
 {{- define "constraint_base" -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
+ALTER TABLE {{qual_table_raw .SchemaName .TableName}}
   ADD CONSTRAINT {{.ConstraintName}}
   {{block "constraint_definition" .}}{{end}};
 {{- end -}}
@@ -15,7 +15,7 @@ BEGIN
           AND table_name = '{{.TableName}}'
           AND constraint_name = '{{.ConstraintName}}'
     ) THEN
-        ALTER TABLE {{.SchemaName}}.{{.TableName}}
+        ALTER TABLE {{qual_table_raw .SchemaName .TableName}}
           DROP CONSTRAINT {{.ConstraintName}};
     END IF;
 END;

pkg/writers/pgsql/templates/base_ddl.tmpl

@@ -11,7 +11,7 @@
 
 {{/* Base ALTER TABLE structure */}}
 {{- define "alter_table_base" -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
+ALTER TABLE {{qual_table_raw .SchemaName .TableName}}
   {{block "alter_operation" .}}{{end}};
 {{- end -}}
 
@@ -30,5 +30,5 @@ $$;
 
 {{/* Common drop pattern */}}
 {{- define "drop_if_exists" -}}
-{{block "drop_type" .}}{{end}} IF EXISTS {{.SchemaName}}.{{.ObjectName}};
+{{block "drop_type" .}}{{end}} IF EXISTS {{qual_table_raw .SchemaName .ObjectName}};
 {{- end -}}

pkg/writers/pgsql/templates/comment_column.tmpl

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

pkg/writers/pgsql/templates/comment_table.tmpl

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

pkg/writers/pgsql/templates/create_check_constraint.tmpl

@@ -6,7 +6,7 @@ BEGIN
       AND table_name = '{{.TableName}}'
       AND constraint_name = '{{.ConstraintName}}'
   ) THEN
-    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} CHECK ({{.Expression}});
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} CHECK ({{.Expression}});
   END IF;
 END;
 $$;

pkg/writers/pgsql/templates/create_foreign_key.tmpl

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

pkg/writers/pgsql/templates/create_foreign_key_with_check.tmpl

@@ -6,10 +6,10 @@ BEGIN
       AND table_name = '{{.TableName}}'
       AND constraint_name = '{{.ConstraintName}}'
   ) THEN
-    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+    ALTER TABLE {{qual_table .SchemaName .TableName}}
       ADD CONSTRAINT {{quote_ident .ConstraintName}}
       FOREIGN KEY ({{.SourceColumns}})
-      REFERENCES {{quote_ident .TargetSchema}}.{{quote_ident .TargetTable}} ({{.TargetColumns}})
+      REFERENCES {{qual_table .TargetSchema .TargetTable}} ({{.TargetColumns}})
       ON DELETE {{.OnDelete}}
       ON UPDATE {{.OnUpdate}}{{if .Deferrable}}
       DEFERRABLE{{end}};

pkg/writers/pgsql/templates/create_index.tmpl

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

pkg/writers/pgsql/templates/create_primary_key.tmpl

@@ -6,7 +6,7 @@ BEGIN
       AND table_name = '{{.TableName}}'
       AND constraint_name = '{{.ConstraintName}}'
   ) THEN
-    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+    ALTER TABLE {{qual_table .SchemaName .TableName}}
       ADD CONSTRAINT {{quote_ident .ConstraintName}} PRIMARY KEY ({{.Columns}});
   END IF;
 END;

pkg/writers/pgsql/templates/create_primary_key_with_autogen_check.tmpl

@@ -11,7 +11,7 @@ BEGIN
     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);
+    EXECUTE 'ALTER TABLE {{qual_table .SchemaName .TableName}} DROP CONSTRAINT ' || quote_ident(auto_pk_name);
   END IF;
 
   -- Add named primary key if it doesn't exist
@@ -21,7 +21,7 @@ BEGIN
       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}});
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} PRIMARY KEY ({{.Columns}});
   END IF;
 END;
 $$;

pkg/writers/pgsql/templates/create_sequence.tmpl

@@ -1,4 +1,4 @@
-CREATE SEQUENCE IF NOT EXISTS {{quote_ident .SchemaName}}.{{quote_ident .SequenceName}}
+CREATE SEQUENCE IF NOT EXISTS {{qual_table .SchemaName .SequenceName}}
   INCREMENT {{.Increment}}
   MINVALUE {{.MinValue}}
   MAXVALUE {{.MaxValue}}

pkg/writers/pgsql/templates/create_table.tmpl

@@ -1,4 +1,4 @@
-CREATE TABLE IF NOT EXISTS {{quote_ident .SchemaName}}.{{quote_ident .TableName}} (
+CREATE TABLE IF NOT EXISTS {{qual_table .SchemaName .TableName}} (
 {{- range $i, $col := .Columns}}
 {{- if $i}},{{end}}
   {{quote_ident $col.Name}} {{$col.Type}}

pkg/writers/pgsql/templates/create_unique_constraint.tmpl

@@ -6,7 +6,7 @@ BEGIN
       AND table_name = '{{.TableName}}'
       AND constraint_name = '{{.ConstraintName}}'
   ) THEN
-    ALTER TABLE {{quote_ident .SchemaName}}.{{quote_ident .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} UNIQUE ({{.Columns}});
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} UNIQUE ({{.Columns}});
   END IF;
 END;
 $$;

pkg/writers/pgsql/templates/drop_constraint.tmpl

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

pkg/writers/pgsql/templates/drop_index.tmpl

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

pkg/writers/pgsql/templates/fragments.tmpl

@@ -16,7 +16,7 @@
 
 {{/* Qualified table name */}}
 {{- define "qualified_table" -}}
-{{.SchemaName}}.{{.TableName}}
+{{qual_table_raw .SchemaName .TableName}}
 {{- end -}}
 
 {{/* Index method clause */}}

pkg/writers/pgsql/templates/set_sequence_value.tmpl

@@ -10,10 +10,10 @@ BEGIN
       AND c.relkind = 'S'
   ) THEN
     SELECT COALESCE(MAX({{quote_ident .ColumnName}}), 0) + 1
-    FROM {{quote_ident .SchemaName}}.{{quote_ident .TableName}}
+    FROM {{qual_table .SchemaName .TableName}}
     INTO m_cnt;
     
-    PERFORM setval('{{quote_ident .SchemaName}}.{{quote_ident .SequenceName}}'::regclass, m_cnt);
+    PERFORM setval('{{qual_table_raw .SchemaName .SequenceName}}'::regclass, m_cnt);
   END IF;
 END;
 $$;

pkg/writers/pgsql/writer.go

@@ -58,13 +58,18 @@ type ExecutionError struct {
 
 // NewWriter creates a new PostgreSQL SQL writer
 func NewWriter(options *writers.WriterOptions) *Writer {
-	executor, _ := NewTemplateExecutor()
+	executor, _ := NewTemplateExecutor(options.FlattenSchema)
 	return &Writer{
 		options:  options,
 		executor: executor,
 	}
 }
 
+// qualTable returns a schema-qualified name using the writer's FlattenSchema setting.
+func (w *Writer) qualTable(schema, name string) string {
+	return writers.QualifiedTableName(schema, name, w.options.FlattenSchema)
+}
+
 // WriteDatabase writes the entire database schema as SQL
 func (w *Writer) WriteDatabase(db *models.Database) error {
 	// Check if we should execute SQL directly on a database
@@ -134,8 +139,8 @@ func (w *Writer) GenerateDatabaseStatements(db *models.Database) ([]string, erro
 func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, error) {
 	statements := []string{}
 
-	// Phase 1: Create schema
+	// Phase 1: Create schema (skip entirely when flattening)
-	if schema.Name != "public" {
+	if schema.Name != "public" && !w.options.FlattenSchema {
 		statements = append(statements, fmt.Sprintf("-- Schema: %s", schema.Name))
 		statements = append(statements, fmt.Sprintf("CREATE SCHEMA IF NOT EXISTS %s", schema.SQLName()))
 	}
@@ -157,8 +162,8 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 			continue
 		}
 
-		stmt := fmt.Sprintf("CREATE SEQUENCE IF NOT EXISTS %s.%s\n  INCREMENT 1\n  MINVALUE 1\n  MAXVALUE 9223372036854775807\n  START 1\n  CACHE 1",
+		stmt := fmt.Sprintf("CREATE SEQUENCE IF NOT EXISTS %s\n  INCREMENT 1\n  MINVALUE 1\n  MAXVALUE 9223372036854775807\n  START 1\n  CACHE 1",
-			schema.SQLName(), seqName)
+			w.qualTable(schema.SQLName(), seqName))
 		statements = append(statements, stmt)
 	}
 
@@ -275,8 +280,8 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				whereClause = fmt.Sprintf(" WHERE %s", index.Where)
 			}
 
-			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s.%s USING %s (%s)%s",
+			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s USING %s (%s)%s",
-				uniqueStr, quoteIdentifier(index.Name), schema.SQLName(), table.SQLName(), indexType, strings.Join(columnExprs, ", "), whereClause)
+				uniqueStr, quoteIdentifier(index.Name), w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), whereClause)
 			statements = append(statements, stmt)
 		}
 	}
@@ -374,15 +379,15 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 	// Phase 7: Comments
 	for _, table := range schema.Tables {
 		if table.Comment != "" {
-			stmt := fmt.Sprintf("COMMENT ON TABLE %s.%s IS '%s'",
+			stmt := fmt.Sprintf("COMMENT ON TABLE %s IS '%s'",
-				schema.SQLName(), table.SQLName(), escapeQuote(table.Comment))
+				w.qualTable(schema.SQLName(), table.SQLName()), escapeQuote(table.Comment))
 			statements = append(statements, stmt)
 		}
 
 		for _, column := range table.Columns {
 			if column.Comment != "" {
-				stmt := fmt.Sprintf("COMMENT ON COLUMN %s.%s.%s IS '%s'",
+				stmt := fmt.Sprintf("COMMENT ON COLUMN %s.%s IS '%s'",
-					schema.SQLName(), table.SQLName(), column.SQLName(), escapeQuote(column.Comment))
+					w.qualTable(schema.SQLName(), table.SQLName()), column.SQLName(), escapeQuote(column.Comment))
 				statements = append(statements, stmt)
 			}
 		}
@@ -474,8 +479,8 @@ func (w *Writer) generateCreateTableStatement(schema *models.Schema, table *mode
 		columnDefs = append(columnDefs, "  "+def)
 	}
 
-	stmt := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s.%s (\n%s\n)",
+	stmt := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s (\n%s\n)",
-		schema.SQLName(), table.SQLName(), strings.Join(columnDefs, ",\n"))
+		w.qualTable(schema.SQLName(), table.SQLName()), strings.Join(columnDefs, ",\n"))
 	statements = append(statements, stmt)
 
 	return statements, nil
@@ -655,8 +660,7 @@ func (w *Writer) WriteAddColumnStatements(db *models.Database) error {
 
 // writeCreateSchema generates CREATE SCHEMA statement
 func (w *Writer) writeCreateSchema(schema *models.Schema) error {
-	if schema.Name == "public" {
+	if schema.Name == "public" || w.options.FlattenSchema {
-		// public schema exists by default
 		return nil
 	}
 
@@ -708,8 +712,8 @@ func (w *Writer) writeCreateTables(schema *models.Schema) error {
 	fmt.Fprintf(w.writer, "-- Tables for schema: %s\n", schema.Name)
 
 	for _, table := range schema.Tables {
-		fmt.Fprintf(w.writer, "CREATE TABLE IF NOT EXISTS %s.%s (\n",
+		fmt.Fprintf(w.writer, "CREATE TABLE IF NOT EXISTS %s (\n",
-			schema.SQLName(), table.SQLName())
+			w.qualTable(schema.SQLName(), table.SQLName()))
 
 		// Write columns
 		columns := getSortedColumns(table.Columns)
@@ -893,8 +897,8 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 
 			fmt.Fprintf(w.writer, "CREATE %sINDEX IF NOT EXISTS %s\n",
 				unique, indexName)
-			fmt.Fprintf(w.writer, "  ON %s.%s USING %s (%s)%s;\n\n",
+			fmt.Fprintf(w.writer, "  ON %s USING %s (%s)%s;\n\n",
-				schema.SQLName(), table.SQLName(), indexType, strings.Join(columnExprs, ", "), whereClause)
+				w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), whereClause)
 		}
 	}
 
@@ -1203,16 +1207,16 @@ func (w *Writer) writeComments(schema *models.Schema) error {
 	for _, table := range schema.Tables {
 		// Table comment
 		if table.Description != "" {
-			fmt.Fprintf(w.writer, "COMMENT ON TABLE %s.%s IS '%s';\n",
+			fmt.Fprintf(w.writer, "COMMENT ON TABLE %s IS '%s';\n",
-				schema.SQLName(), table.SQLName(),
+				w.qualTable(schema.SQLName(), table.SQLName()),
 				escapeQuote(table.Description))
 		}
 
 		// Column comments
 		for _, col := range getSortedColumns(table.Columns) {
 			if col.Description != "" {
-				fmt.Fprintf(w.writer, "COMMENT ON COLUMN %s.%s.%s IS '%s';\n",
+				fmt.Fprintf(w.writer, "COMMENT ON COLUMN %s.%s IS '%s';\n",
-					schema.SQLName(), table.SQLName(), col.SQLName(),
+					w.qualTable(schema.SQLName(), table.SQLName()), col.SQLName(),
 					escapeQuote(col.Description))
 			}
 		}

pkg/writers/writer.go

@@ -28,10 +28,29 @@ type WriterOptions struct {
 	// PackageName is the Go package name (for code generation)
 	PackageName string
 
+	// FlattenSchema disables schema.table dot notation and instead joins
+	// schema and table with an underscore (e.g., "public_users").
+	// Useful for databases like SQLite that do not support schemas.
+	FlattenSchema bool
+
 	// Additional options can be added here as needed
 	Metadata map[string]interface{}
 }
 
+// QualifiedTableName returns a schema-qualified table name.
+// When flatten is true, schema and table are joined with underscore (e.g., "schema_table").
+// When flatten is false, they are dot-separated (e.g., "schema.table").
+// If schema is empty, just the table name is returned regardless of flatten.
+func QualifiedTableName(schema, table string, flatten bool) string {
+	if schema == "" {
+		return table
+	}
+	if flatten {
+		return schema + "_" + table
+	}
+	return schema + "." + table
+}
+
 // SanitizeFilename removes quotes, comments, and invalid characters from identifiers
 // to make them safe for use in filenames. This handles:
 // - Double and single quotes: "table_name" or 'table_name' -> table_name