Fixed double .Model and .Table

pkg/common/adapters/database/bun.go

@@ -9,6 +9,8 @@ import (
 	"github.com/uptrace/bun"
 
 	"github.com/bitechdev/ResolveSpec/pkg/common"
+	"github.com/bitechdev/ResolveSpec/pkg/modelregistry"
+	"github.com/bitechdev/ResolveSpec/pkg/reflection"
 )
 
 // BunAdapter adapts Bun to work with our Database interface
@@ -353,25 +355,50 @@ func (b *BunInsertQuery) Exec(ctx context.Context) (common.Result, error) {
 // BunUpdateQuery implements UpdateQuery for Bun
 type BunUpdateQuery struct {
 	query *bun.UpdateQuery
+	model interface{}
 }
 
 func (b *BunUpdateQuery) Model(model interface{}) common.UpdateQuery {
 	b.query = b.query.Model(model)
+	b.model = model
 	return b
 }
 
 func (b *BunUpdateQuery) Table(table string) common.UpdateQuery {
 	b.query = b.query.Table(table)
+	if b.model == nil {
+		// Try to get table name from table string if model is not set
+
+		model, err := modelregistry.GetModelByName(table)
+		if err == nil {
+			b.model = model
+		}
+	}
 	return b
 }
 
 func (b *BunUpdateQuery) Set(column string, value interface{}) common.UpdateQuery {
+	// Validate column is writable if model is set
+	if b.model != nil && !reflection.IsColumnWritable(b.model, column) {
+		// Skip scan-only columns
+		return b
+	}
 	b.query = b.query.Set(column+" = ?", value)
 	return b
 }
 
 func (b *BunUpdateQuery) SetMap(values map[string]interface{}) common.UpdateQuery {
+	pkName := reflection.GetPrimaryKeyName(b.model)
 	for column, value := range values {
+		// Validate column is writable if model is set
+		if b.model != nil && !reflection.IsColumnWritable(b.model, column) {
+			// Skip scan-only columns
+			continue
+		}
+		if pkName != "" && column == pkName {
+			// Skip primary key updates
+			continue
+		}
 		b.query = b.query.Set(column+" = ?", value)
 	}
 	return b

pkg/common/adapters/database/gorm.go

@@ -8,6 +8,8 @@ import (
 	"gorm.io/gorm"
 
 	"github.com/bitechdev/ResolveSpec/pkg/common"
+	"github.com/bitechdev/ResolveSpec/pkg/modelregistry"
+	"github.com/bitechdev/ResolveSpec/pkg/reflection"
 )
 
 // GormAdapter adapts GORM to work with our Database interface
@@ -97,6 +99,7 @@ func (g *GormSelectQuery) Table(table string) common.SelectQuery {
 	g.db = g.db.Table(table)
 	// Check if the table name contains schema (e.g., "schema.table")
 	g.schema, g.tableName = parseTableName(table)
+
 	return g
 }
 
@@ -339,10 +342,23 @@ func (g *GormUpdateQuery) Model(model interface{}) common.UpdateQuery {
 
 func (g *GormUpdateQuery) Table(table string) common.UpdateQuery {
 	g.db = g.db.Table(table)
+	if g.model == nil {
+		// Try to get table name from table string if model is not set
+		model, err := modelregistry.GetModelByName(table)
+		if err == nil {
+			g.model = model
+		}
+	}
 	return g
 }
 
 func (g *GormUpdateQuery) Set(column string, value interface{}) common.UpdateQuery {
+	// Validate column is writable if model is set
+	if g.model != nil && !reflection.IsColumnWritable(g.model, column) {
+		// Skip read-only columns
+		return g
+	}
+
 	if g.updates == nil {
 		g.updates = make(map[string]interface{})
 	}
@@ -353,7 +369,25 @@ func (g *GormUpdateQuery) Set(column string, value interface{}) common.UpdateQue
 }
 
 func (g *GormUpdateQuery) SetMap(values map[string]interface{}) common.UpdateQuery {
-	g.updates = values
+
+	// Filter out read-only columns if model is set
+	if g.model != nil {
+		pkName := reflection.GetPrimaryKeyName(g.model)
+		filteredValues := make(map[string]interface{})
+		for column, value := range values {
+			if pkName != "" && column == pkName {
+				// Skip primary key updates
+				continue
+			}
+			if reflection.IsColumnWritable(g.model, column) {
+				filteredValues[column] = value
+			}
+
+		}
+		g.updates = filteredValues
+	} else {
+		g.updates = values
+	}
 	return g
 }
 

pkg/common/adapters/database/update_validation_test.go

@@ -0,0 +1,161 @@
+package database
+
+import (
+	"testing"
+
+	"github.com/bitechdev/ResolveSpec/pkg/reflection"
+)
+
+// Test models for bun
+type BunTestModel struct {
+	ID          int    `bun:"id,pk"`
+	Name        string `bun:"name"`
+	Email       string `bun:"email"`
+	ComputedCol string `bun:"computed_col,scanonly"`
+}
+
+// Test models for gorm
+type GormTestModel struct {
+	ID          int    `gorm:"column:id;primaryKey"`
+	Name        string `gorm:"column:name"`
+	Email       string `gorm:"column:email"`
+	ReadOnlyCol string `gorm:"column:readonly_col;->"`
+	NoWriteCol  string `gorm:"column:nowrite_col;<-:false"`
+}
+
+func TestIsColumnWritable_Bun(t *testing.T) {
+	model := &BunTestModel{}
+
+	tests := []struct {
+		name       string
+		columnName string
+		expected   bool
+	}{
+		{
+			name:       "writable column - id",
+			columnName: "id",
+			expected:   true,
+		},
+		{
+			name:       "writable column - name",
+			columnName: "name",
+			expected:   true,
+		},
+		{
+			name:       "writable column - email",
+			columnName: "email",
+			expected:   true,
+		},
+		{
+			name:       "scanonly column should not be writable",
+			columnName: "computed_col",
+			expected:   false,
+		},
+		{
+			name:       "non-existent column should be writable (dynamic)",
+			columnName: "nonexistent",
+			expected:   true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := reflection.IsColumnWritable(model, tt.columnName)
+			if result != tt.expected {
+				t.Errorf("IsColumnWritable(%q) = %v, want %v", tt.columnName, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestIsColumnWritable_Gorm(t *testing.T) {
+	model := &GormTestModel{}
+
+	tests := []struct {
+		name       string
+		columnName string
+		expected   bool
+	}{
+		{
+			name:       "writable column - id",
+			columnName: "id",
+			expected:   true,
+		},
+		{
+			name:       "writable column - name",
+			columnName: "name",
+			expected:   true,
+		},
+		{
+			name:       "writable column - email",
+			columnName: "email",
+			expected:   true,
+		},
+		{
+			name:       "read-only column with -> should not be writable",
+			columnName: "readonly_col",
+			expected:   false,
+		},
+		{
+			name:       "column with <-:false should not be writable",
+			columnName: "nowrite_col",
+			expected:   false,
+		},
+		{
+			name:       "non-existent column should be writable (dynamic)",
+			columnName: "nonexistent",
+			expected:   true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := reflection.IsColumnWritable(model, tt.columnName)
+			if result != tt.expected {
+				t.Errorf("IsColumnWritable(%q) = %v, want %v", tt.columnName, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestBunUpdateQuery_SetMap_FiltersScanOnly(t *testing.T) {
+	// Note: This is a unit test for the validation logic only.
+	// We can't fully test the bun query without a database connection,
+	// but we've verified the validation logic in TestIsColumnWritable_Bun
+	t.Skip("Skipping integration test - validation logic tested in TestIsColumnWritable_Bun")
+}
+
+func TestGormUpdateQuery_SetMap_FiltersReadOnly(t *testing.T) {
+	model := &GormTestModel{}
+	query := &GormUpdateQuery{
+		model: model,
+	}
+
+	// SetMap should filter out read-only columns
+	values := map[string]interface{}{
+		"name":         "John",
+		"email":        "john@example.com",
+		"readonly_col": "should_be_filtered",
+		"nowrite_col":  "should_also_be_filtered",
+	}
+
+	query.SetMap(values)
+
+	// Check that the updates map only contains writable columns
+	if updates, ok := query.updates.(map[string]interface{}); ok {
+		if _, exists := updates["readonly_col"]; exists {
+			t.Error("readonly_col should have been filtered out")
+		}
+		if _, exists := updates["nowrite_col"]; exists {
+			t.Error("nowrite_col should have been filtered out")
+		}
+		if _, exists := updates["name"]; !exists {
+			t.Error("name should be in updates")
+		}
+		if _, exists := updates["email"]; !exists {
+			t.Error("email should be in updates")
+		}
+	} else {
+		t.Error("updates should be a map[string]interface{}")
+	}
+}

pkg/common/recursive_crud.go

@@ -111,6 +111,9 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 	// Inject parent IDs for foreign key resolution
 	p.injectForeignKeys(regularData, modelType, parentIDs)
 
+	// Get the primary key name for this model
+	pkName := reflection.GetPrimaryKeyName(model)
+
 	// Process based on operation
 	switch strings.ToLower(operation) {
 	case "insert", "create":
@@ -128,30 +131,30 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 		}
 
 	case "update":
-		rows, err := p.processUpdate(ctx, regularData, tableName, data["id"])
+		rows, err := p.processUpdate(ctx, regularData, tableName, data[pkName])
 		if err != nil {
 			return nil, fmt.Errorf("update failed: %w", err)
 		}
-		result.ID = data["id"]
+		result.ID = data[pkName]
 		result.AffectedRows = rows
 		result.Data = regularData
 
 		// Process child relations for update
-		if err := p.processChildRelations(ctx, "update", data["id"], relationFields, result.RelationData, modelType); err != nil {
+		if err := p.processChildRelations(ctx, "update", data[pkName], relationFields, result.RelationData, modelType); err != nil {
 			return nil, fmt.Errorf("failed to process child relations: %w", err)
 		}
 
 	case "delete":
 		// Process child relations first (for referential integrity)
-		if err := p.processChildRelations(ctx, "delete", data["id"], relationFields, result.RelationData, modelType); err != nil {
+		if err := p.processChildRelations(ctx, "delete", data[pkName], relationFields, result.RelationData, modelType); err != nil {
 			return nil, fmt.Errorf("failed to process child relations before delete: %w", err)
 		}
 
-		rows, err := p.processDelete(ctx, tableName, data["id"])
+		rows, err := p.processDelete(ctx, tableName, data[pkName])
 		if err != nil {
 			return nil, fmt.Errorf("delete failed: %w", err)
 		}
-		result.ID = data["id"]
+		result.ID = data[pkName]
 		result.AffectedRows = rows
 		result.Data = regularData
 
@@ -378,8 +381,16 @@ func (p *NestedCUDProcessor) getTableNameForModel(model interface{}, defaultName
 }
 
 // ShouldUseNestedProcessor determines if we should use nested CUD processing
-// It checks if the data contains nested relations or a _request field
+// It recursively checks if the data contains:
+// 1. A _request field at any level, OR
+// 2. Nested relations that themselves contain further nested relations or _request fields
+// This ensures nested processing is only used when there are deeply nested operations
 func ShouldUseNestedProcessor(data map[string]interface{}, model interface{}, relationshipHelper RelationshipInfoProvider) bool {
+	return shouldUseNestedProcessorDepth(data, model, relationshipHelper, 0)
+}
+
+// shouldUseNestedProcessorDepth is the internal recursive implementation with depth tracking
+func shouldUseNestedProcessorDepth(data map[string]interface{}, model interface{}, relationshipHelper RelationshipInfoProvider, depth int) bool {
 	// Check for _request field
 	if _, hasCRUDRequest := data["_request"]; hasCRUDRequest {
 		return true
@@ -406,10 +417,34 @@ func ShouldUseNestedProcessor(data map[string]interface{}, model interface{}, re
 		relInfo := relationshipHelper.GetRelationshipInfo(modelType, key)
 		if relInfo != nil {
 			// Check if the value is actually nested data (object or array)
-			switch value.(type) {
+			switch v := value.(type) {
 			case map[string]interface{}, []interface{}, []map[string]interface{}:
-				logger.Debug("Found nested relation field: %s", key)
+				// If we're already at a nested level (depth > 0) and found a relation,
-				return true
+				// that means we have multi-level nesting, so return true
+				if depth > 0 {
+					return true
+				}
+				// At depth 0, recurse to check if the nested data has further nesting
+				switch typedValue := v.(type) {
+				case map[string]interface{}:
+					if shouldUseNestedProcessorDepth(typedValue, relInfo.RelatedModel, relationshipHelper, depth+1) {
+						return true
+					}
+				case []interface{}:
+					for _, item := range typedValue {
+						if itemMap, ok := item.(map[string]interface{}); ok {
+							if shouldUseNestedProcessorDepth(itemMap, relInfo.RelatedModel, relationshipHelper, depth+1) {
+								return true
+							}
+						}
+					}
+				case []map[string]interface{}:
+					for _, itemMap := range typedValue {
+						if shouldUseNestedProcessorDepth(itemMap, relInfo.RelatedModel, relationshipHelper, depth+1) {
+							return true
+						}
+					}
+				}
 			}
 		}
 	}

pkg/modelregistry/model_registry.go

@@ -17,6 +17,10 @@ var defaultRegistry = &DefaultModelRegistry{
 	models: make(map[string]interface{}),
 }
 
+// Global list of registries (searched in order)
+var registries = []*DefaultModelRegistry{defaultRegistry}
+var registriesMutex sync.RWMutex
+
 // NewModelRegistry creates a new model registry
 func NewModelRegistry() *DefaultModelRegistry {
 	return &DefaultModelRegistry{
@@ -24,6 +28,34 @@ func NewModelRegistry() *DefaultModelRegistry {
 	}
 }
 
+func SetDefaultRegistry(registry *DefaultModelRegistry) {
+	registriesMutex.Lock()
+	foundAt := -1
+	for idx, r := range registries {
+		if r == defaultRegistry {
+			foundAt = idx
+			break
+		}
+	}
+	defaultRegistry = registry
+	if foundAt >= 0 {
+		registries[foundAt] = registry
+	} else {
+		registries = append([]*DefaultModelRegistry{registry}, registries...)
+	}
+
+	defer registriesMutex.Unlock()
+
+}
+
+// AddRegistry adds a registry to the global list of registries
+// Registries are searched in the order they were added
+func AddRegistry(registry *DefaultModelRegistry) {
+	registriesMutex.Lock()
+	defer registriesMutex.Unlock()
+	registries = append(registries, registry)
+}
+
 func (r *DefaultModelRegistry) RegisterModel(name string, model interface{}) error {
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
@@ -107,9 +139,19 @@ func RegisterModel(model interface{}, name string) error {
 	return defaultRegistry.RegisterModel(name, model)
 }
 
-// GetModelByName retrieves a model from the default global registry by name
+// GetModelByName retrieves a model by searching through all registries in order
+// Returns the first match found
 func GetModelByName(name string) (interface{}, error) {
-	return defaultRegistry.GetModel(name)
+	registriesMutex.RLock()
+	defer registriesMutex.RUnlock()
+
+	for _, registry := range registries {
+		if model, err := registry.GetModel(name); err == nil {
+			return model, nil
+		}
+	}
+
+	return nil, fmt.Errorf("model %s not found in any registry", name)
 }
 
 // IterateModels iterates over all models in the default global registry
@@ -122,14 +164,26 @@ func IterateModels(fn func(name string, model interface{})) {
 	}
 }
 
-// GetModels returns a list of all models in the default global registry
+// GetModels returns a list of all models from all registries
+// Models are collected in registry order, with duplicates included
 func GetModels() []interface{} {
-	defaultRegistry.mutex.RLock()
+	registriesMutex.RLock()
-	defer defaultRegistry.mutex.RUnlock()
+	defer registriesMutex.RUnlock()
 
-	models := make([]interface{}, 0, len(defaultRegistry.models))
+	var models []interface{}
-	for _, model := range defaultRegistry.models {
+	seen := make(map[string]bool)
-		models = append(models, model)
+
+	for _, registry := range registries {
+		registry.mutex.RLock()
+		for name, model := range registry.models {
+			// Only add the first occurrence of each model name
+			if !seen[name] {
+				models = append(models, model)
+				seen[name] = true
+			}
+		}
+		registry.mutex.RUnlock()
 	}
+
 	return models
 }

pkg/reflection/generic_model.go

@@ -18,6 +18,7 @@ type ModelFieldDetail struct {
 }
 
 // GetModelColumnDetail - Get a list of columns in the SQL declaration of the model
+// This function recursively processes embedded structs to include their fields
 func GetModelColumnDetail(record reflect.Value) []ModelFieldDetail {
 	defer func() {
 		if r := recover(); r != nil {
@@ -37,14 +38,43 @@ func GetModelColumnDetail(record reflect.Value) []ModelFieldDetail {
 	if record.Kind() != reflect.Struct {
 		return lst
 	}
+
+	collectFieldDetails(record, &lst)
+
+	return lst
+}
+
+// collectFieldDetails recursively collects field details from a struct value and its embedded fields
+func collectFieldDetails(record reflect.Value, lst *[]ModelFieldDetail) {
 	modeltype := record.Type()
 
 	for i := 0; i < modeltype.NumField(); i++ {
 		fieldtype := modeltype.Field(i)
+		fieldValue := record.Field(i)
+
+		// Check if this is an embedded struct
+		if fieldtype.Anonymous {
+			// Unwrap pointer type if necessary
+			embeddedValue := fieldValue
+			if fieldValue.Kind() == reflect.Pointer {
+				if fieldValue.IsNil() {
+					// Skip nil embedded pointers
+					continue
+				}
+				embeddedValue = fieldValue.Elem()
+			}
+
+			// Recursively process embedded struct
+			if embeddedValue.Kind() == reflect.Struct {
+				collectFieldDetails(embeddedValue, lst)
+				continue
+			}
+		}
+
 		gormdetail := fieldtype.Tag.Get("gorm")
 		gormdetail = strings.Trim(gormdetail, " ")
 		fielddetail := ModelFieldDetail{}
-		fielddetail.FieldValue = record.Field(i)
+		fielddetail.FieldValue = fieldValue
 		fielddetail.Name = fieldtype.Name
 		fielddetail.DataType = fieldtype.Type.Name()
 		fielddetail.SQLName = fnFindKeyVal(gormdetail, "column:")
@@ -80,10 +110,8 @@ func GetModelColumnDetail(record reflect.Value) []ModelFieldDetail {
 		}
 		// ";foreignkey:rid_parent;association_foreignkey:id_atevent;save_associations:false;association_autocreate:false;"
 
-		lst = append(lst, fielddetail)
+		*lst = append(*lst, fielddetail)
-
 	}
-	return lst
 }
 
 func fnFindKeyVal(src, key string) string {

pkg/reflection/model_utils.go

@@ -45,8 +45,104 @@ func GetPrimaryKeyName(model any) string {
 	return ""
 }
 
+// GetPrimaryKeyValue extracts the primary key value from a model instance
+// Returns the value of the primary key field
+func GetPrimaryKeyValue(model any) any {
+	if model == nil || reflect.TypeOf(model) == nil {
+		return nil
+	}
+
+	val := reflect.ValueOf(model)
+	if val.Kind() == reflect.Pointer {
+		val = val.Elem()
+	}
+
+	if val.Kind() != reflect.Struct {
+		return nil
+	}
+
+	// Try Bun tag first
+	if pkValue := findPrimaryKeyValue(val, "bun"); pkValue != nil {
+		return pkValue
+	}
+
+	// Fall back to GORM tag
+	if pkValue := findPrimaryKeyValue(val, "gorm"); pkValue != nil {
+		return pkValue
+	}
+
+	// Last resort: look for field named "ID" or "Id"
+	if pkValue := findFieldByName(val, "id"); pkValue != nil {
+		return pkValue
+	}
+
+	return nil
+}
+
+// findPrimaryKeyValue recursively searches for a primary key field in the struct
+func findPrimaryKeyValue(val reflect.Value, ormType string) any {
+	typ := val.Type()
+
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+		fieldValue := val.Field(i)
+
+		// Check if this is an embedded struct
+		if field.Anonymous && field.Type.Kind() == reflect.Struct {
+			// Recursively search in embedded struct
+			if pkValue := findPrimaryKeyValue(fieldValue, ormType); pkValue != nil {
+				return pkValue
+			}
+			continue
+		}
+
+		// Check for primary key tag
+		switch ormType {
+		case "bun":
+			bunTag := field.Tag.Get("bun")
+			if strings.Contains(bunTag, "pk") && fieldValue.CanInterface() {
+				return fieldValue.Interface()
+			}
+		case "gorm":
+			gormTag := field.Tag.Get("gorm")
+			if strings.Contains(gormTag, "primaryKey") && fieldValue.CanInterface() {
+				return fieldValue.Interface()
+			}
+		}
+	}
+
+	return nil
+}
+
+// findFieldByName recursively searches for a field by name in the struct
+func findFieldByName(val reflect.Value, name string) any {
+	typ := val.Type()
+
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+		fieldValue := val.Field(i)
+
+		// Check if this is an embedded struct
+		if field.Anonymous && field.Type.Kind() == reflect.Struct {
+			// Recursively search in embedded struct
+			if result := findFieldByName(fieldValue, name); result != nil {
+				return result
+			}
+			continue
+		}
+
+		// Check if field name matches
+		if strings.ToLower(field.Name) == name && fieldValue.CanInterface() {
+			return fieldValue.Interface()
+		}
+	}
+
+	return nil
+}
+
 // GetModelColumns extracts all column names from a model using reflection
 // It checks bun tags first, then gorm tags, then json tags, and finally falls back to lowercase field names
+// This function recursively processes embedded structs to include their fields
 func GetModelColumns(model any) []string {
 	var columns []string
 
@@ -62,18 +158,38 @@ func GetModelColumns(model any) []string {
 		return columns
 	}
 
-	for i := 0; i < modelType.NumField(); i++ {
+	collectColumnsFromType(modelType, &columns)
-		field := modelType.Field(i)
+
+	return columns
+}
+
+// collectColumnsFromType recursively collects column names from a struct type and its embedded fields
+func collectColumnsFromType(typ reflect.Type, columns *[]string) {
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+
+		// Check if this is an embedded struct
+		if field.Anonymous {
+			// Unwrap pointer type if necessary
+			fieldType := field.Type
+			if fieldType.Kind() == reflect.Pointer {
+				fieldType = fieldType.Elem()
+			}
+
+			// Recursively process embedded struct
+			if fieldType.Kind() == reflect.Struct {
+				collectColumnsFromType(fieldType, columns)
+				continue
+			}
+		}
 
 		// Get column name using the same logic as primary key extraction
 		columnName := getColumnNameFromField(field)
 
 		if columnName != "" {
-			columns = append(columns, columnName)
+			*columns = append(*columns, columnName)
 		}
 	}
-
-	return columns
 }
 
 // getColumnNameFromField extracts the column name from a struct field
@@ -110,6 +226,7 @@ func getColumnNameFromField(field reflect.StructField) string {
 }
 
 // getPrimaryKeyFromReflection uses reflection to find the primary key field
+// This function recursively searches embedded structs
 func getPrimaryKeyFromReflection(model any, ormType string) string {
 	val := reflect.ValueOf(model)
 	if val.Kind() == reflect.Pointer {
@@ -121,9 +238,31 @@ func getPrimaryKeyFromReflection(model any, ormType string) string {
 	}
 
 	typ := val.Type()
+	return findPrimaryKeyNameFromType(typ, ormType)
+}
+
+// findPrimaryKeyNameFromType recursively searches for the primary key field name in a struct type
+func findPrimaryKeyNameFromType(typ reflect.Type, ormType string) string {
 	for i := 0; i < typ.NumField(); i++ {
 		field := typ.Field(i)
 
+		// Check if this is an embedded struct
+		if field.Anonymous {
+			// Unwrap pointer type if necessary
+			fieldType := field.Type
+			if fieldType.Kind() == reflect.Pointer {
+				fieldType = fieldType.Elem()
+			}
+
+			// Recursively search in embedded struct
+			if fieldType.Kind() == reflect.Struct {
+				if pkName := findPrimaryKeyNameFromType(fieldType, ormType); pkName != "" {
+					return pkName
+				}
+			}
+			continue
+		}
+
 		switch ormType {
 		case "gorm":
 			// Check for gorm tag with primaryKey
@@ -175,8 +314,129 @@ func ExtractColumnFromGormTag(tag string) string {
 // Example: ",pk" -> "" (will fall back to json tag)
 func ExtractColumnFromBunTag(tag string) string {
 	parts := strings.Split(tag, ",")
+	if strings.HasPrefix(strings.ToLower(tag), "table:") || strings.HasPrefix(strings.ToLower(tag), "rel:") || strings.HasPrefix(strings.ToLower(tag), "join:") {
+		return ""
+	}
 	if len(parts) > 0 && parts[0] != "" {
 		return parts[0]
 	}
 	return ""
 }
+
+// IsColumnWritable checks if a column can be written to in the database
+// For bun: returns false if the field has "scanonly" tag
+// For gorm: returns false if the field has "<-:false" or "->" (read-only) tag
+// This function recursively searches embedded structs
+func IsColumnWritable(model any, columnName string) bool {
+	modelType := reflect.TypeOf(model)
+
+	// Unwrap pointers to get to the base struct type
+	for modelType != nil && modelType.Kind() == reflect.Pointer {
+		modelType = modelType.Elem()
+	}
+
+	// Validate that we have a struct type
+	if modelType == nil || modelType.Kind() != reflect.Struct {
+		return false
+	}
+
+	found, writable := isColumnWritableInType(modelType, columnName)
+	if found {
+		return writable
+	}
+
+	// Column not found in model, allow it (might be a dynamic column)
+	return true
+}
+
+// isColumnWritableInType recursively searches for a column and checks if it's writable
+// Returns (found, writable) where found indicates if the column was found
+func isColumnWritableInType(typ reflect.Type, columnName string) (bool, bool) {
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+
+		// Check if this is an embedded struct
+		if field.Anonymous {
+			// Unwrap pointer type if necessary
+			fieldType := field.Type
+			if fieldType.Kind() == reflect.Pointer {
+				fieldType = fieldType.Elem()
+			}
+
+			// Recursively search in embedded struct
+			if fieldType.Kind() == reflect.Struct {
+				if found, writable := isColumnWritableInType(fieldType, columnName); found {
+					return true, writable
+				}
+			}
+			continue
+		}
+
+		// Check if this field matches the column name
+		fieldColumnName := getColumnNameFromField(field)
+		if fieldColumnName != columnName {
+			continue
+		}
+
+		// Found the field, now check if it's writable
+		// Check bun tag for scanonly
+		bunTag := field.Tag.Get("bun")
+		if bunTag != "" {
+			if isBunFieldScanOnly(bunTag) {
+				return true, false
+			}
+		}
+
+		// Check gorm tag for write restrictions
+		gormTag := field.Tag.Get("gorm")
+		if gormTag != "" {
+			if isGormFieldReadOnly(gormTag) {
+				return true, false
+			}
+		}
+
+		// Column is writable
+		return true, true
+	}
+
+	// Column not found
+	return false, false
+}
+
+// isBunFieldScanOnly checks if a bun tag indicates the field is scan-only
+// Example: "column_name,scanonly" -> true
+func isBunFieldScanOnly(tag string) bool {
+	parts := strings.Split(tag, ",")
+	for _, part := range parts {
+		if strings.TrimSpace(part) == "scanonly" {
+			return true
+		}
+	}
+	return false
+}
+
+// isGormFieldReadOnly checks if a gorm tag indicates the field is read-only
+// Examples:
+//   - "<-:false" -> true (no writes allowed)
+//   - "->" -> true (read-only, common pattern)
+//   - "column:name;->" -> true
+//   - "<-:create" -> false (writes allowed on create)
+func isGormFieldReadOnly(tag string) bool {
+	parts := strings.Split(tag, ";")
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+
+		// Check for read-only marker
+		if part == "->" {
+			return true
+		}
+
+		// Check for write restrictions
+		if value, found := strings.CutPrefix(part, "<-:"); found {
+			if value == "false" {
+				return true
+			}
+		}
+	}
+	return false
+}

pkg/reflection/model_utils_test.go

@@ -231,3 +231,246 @@ func TestGetModelColumns(t *testing.T) {
 		})
 	}
 }
+
+// Test models with embedded structs
+
+type BaseModel struct {
+	ID        int    `bun:"rid_base,pk" json:"id"`
+	CreatedAt string `bun:"created_at" json:"created_at"`
+}
+
+type AdhocBuffer struct {
+	CQL1      string `json:"cql1,omitempty" gorm:"->" bun:",scanonly"`
+	CQL2      string `json:"cql2,omitempty" gorm:"->" bun:",scanonly"`
+	RowNumber int64  `json:"_rownumber,omitempty" gorm:"-" bun:",scanonly"`
+}
+
+type ModelWithEmbedded struct {
+	BaseModel
+	Name        string `bun:"name" json:"name"`
+	Description string `bun:"description" json:"description"`
+	AdhocBuffer
+}
+
+type GormBaseModel struct {
+	ID        int    `gorm:"column:rid_base;primaryKey" json:"id"`
+	CreatedAt string `gorm:"column:created_at" json:"created_at"`
+}
+
+type GormAdhocBuffer struct {
+	CQL1      string `json:"cql1,omitempty" gorm:"column:cql1;->" bun:",scanonly"`
+	CQL2      string `json:"cql2,omitempty" gorm:"column:cql2;->" bun:",scanonly"`
+	RowNumber int64  `json:"_rownumber,omitempty" gorm:"-" bun:",scanonly"`
+}
+
+type GormModelWithEmbedded struct {
+	GormBaseModel
+	Name        string `gorm:"column:name" json:"name"`
+	Description string `gorm:"column:description" json:"description"`
+	GormAdhocBuffer
+}
+
+func TestGetPrimaryKeyNameWithEmbedded(t *testing.T) {
+	tests := []struct {
+		name     string
+		model    any
+		expected string
+	}{
+		{
+			name:     "Bun model with embedded base",
+			model:    ModelWithEmbedded{},
+			expected: "rid_base",
+		},
+		{
+			name:     "Bun model with embedded base (pointer)",
+			model:    &ModelWithEmbedded{},
+			expected: "rid_base",
+		},
+		{
+			name:     "GORM model with embedded base",
+			model:    GormModelWithEmbedded{},
+			expected: "rid_base",
+		},
+		{
+			name:     "GORM model with embedded base (pointer)",
+			model:    &GormModelWithEmbedded{},
+			expected: "rid_base",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := GetPrimaryKeyName(tt.model)
+			if result != tt.expected {
+				t.Errorf("GetPrimaryKeyName() = %v, want %v", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestGetPrimaryKeyValueWithEmbedded(t *testing.T) {
+	bunModel := ModelWithEmbedded{
+		BaseModel: BaseModel{
+			ID:        123,
+			CreatedAt: "2024-01-01",
+		},
+		Name:        "Test",
+		Description: "Test Description",
+	}
+
+	gormModel := GormModelWithEmbedded{
+		GormBaseModel: GormBaseModel{
+			ID:        456,
+			CreatedAt: "2024-01-02",
+		},
+		Name:        "GORM Test",
+		Description: "GORM Test Description",
+	}
+
+	tests := []struct {
+		name     string
+		model    any
+		expected any
+	}{
+		{
+			name:     "Bun model with embedded base",
+			model:    bunModel,
+			expected: 123,
+		},
+		{
+			name:     "Bun model with embedded base (pointer)",
+			model:    &bunModel,
+			expected: 123,
+		},
+		{
+			name:     "GORM model with embedded base",
+			model:    gormModel,
+			expected: 456,
+		},
+		{
+			name:     "GORM model with embedded base (pointer)",
+			model:    &gormModel,
+			expected: 456,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := GetPrimaryKeyValue(tt.model)
+			if result != tt.expected {
+				t.Errorf("GetPrimaryKeyValue() = %v, want %v", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestGetModelColumnsWithEmbedded(t *testing.T) {
+	tests := []struct {
+		name     string
+		model    any
+		expected []string
+	}{
+		{
+			name:     "Bun model with embedded structs",
+			model:    ModelWithEmbedded{},
+			expected: []string{"rid_base", "created_at", "name", "description", "cql1", "cql2", "_rownumber"},
+		},
+		{
+			name:     "Bun model with embedded structs (pointer)",
+			model:    &ModelWithEmbedded{},
+			expected: []string{"rid_base", "created_at", "name", "description", "cql1", "cql2", "_rownumber"},
+		},
+		{
+			name:     "GORM model with embedded structs",
+			model:    GormModelWithEmbedded{},
+			expected: []string{"rid_base", "created_at", "name", "description", "cql1", "cql2", "_rownumber"},
+		},
+		{
+			name:     "GORM model with embedded structs (pointer)",
+			model:    &GormModelWithEmbedded{},
+			expected: []string{"rid_base", "created_at", "name", "description", "cql1", "cql2", "_rownumber"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := GetModelColumns(tt.model)
+			if len(result) != len(tt.expected) {
+				t.Errorf("GetModelColumns() returned %d columns, want %d. Got: %v", len(result), len(tt.expected), result)
+				return
+			}
+			for i, col := range result {
+				if col != tt.expected[i] {
+					t.Errorf("GetModelColumns()[%d] = %v, want %v", i, col, tt.expected[i])
+				}
+			}
+		})
+	}
+}
+
+func TestIsColumnWritableWithEmbedded(t *testing.T) {
+	tests := []struct {
+		name       string
+		model      any
+		columnName string
+		expected   bool
+	}{
+		{
+			name:       "Bun model - writable column in main struct",
+			model:      ModelWithEmbedded{},
+			columnName: "name",
+			expected:   true,
+		},
+		{
+			name:       "Bun model - writable column in embedded base",
+			model:      ModelWithEmbedded{},
+			columnName: "rid_base",
+			expected:   true,
+		},
+		{
+			name:       "Bun model - scanonly column in embedded adhoc buffer",
+			model:      ModelWithEmbedded{},
+			columnName: "cql1",
+			expected:   false,
+		},
+		{
+			name:       "Bun model - scanonly column _rownumber",
+			model:      ModelWithEmbedded{},
+			columnName: "_rownumber",
+			expected:   false,
+		},
+		{
+			name:       "GORM model - writable column in main struct",
+			model:      GormModelWithEmbedded{},
+			columnName: "name",
+			expected:   true,
+		},
+		{
+			name:       "GORM model - writable column in embedded base",
+			model:      GormModelWithEmbedded{},
+			columnName: "rid_base",
+			expected:   true,
+		},
+		{
+			name:       "GORM model - readonly column in embedded adhoc buffer",
+			model:      GormModelWithEmbedded{},
+			columnName: "cql1",
+			expected:   false,
+		},
+		{
+			name:       "GORM model - readonly column _rownumber",
+			model:      GormModelWithEmbedded{},
+			columnName: "_rownumber",
+			expected:   false, // bun:",scanonly" marks it as read-only, takes precedence over gorm:"-"
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := IsColumnWritable(tt.model, tt.columnName)
+			if result != tt.expected {
+				t.Errorf("IsColumnWritable(%s) = %v, want %v", tt.columnName, result, tt.expected)
+			}
+		})
+	}
+}

pkg/restheadspec/handler.go

@@ -584,22 +584,6 @@ func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, dat
 
 	logger.Info("Creating record in %s.%s", schema, entity)
 
-	// Check if data is a single map with nested relations
-	if dataMap, ok := data.(map[string]interface{}); ok {
-		if h.shouldUseNestedProcessor(dataMap, model) {
-			logger.Info("Using nested CUD processor for create operation")
-			result, err := h.nestedProcessor.ProcessNestedCUD(ctx, "insert", dataMap, model, make(map[string]interface{}), tableName)
-			if err != nil {
-				logger.Error("Error in nested create: %v", err)
-				h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating record with nested data", err)
-				return
-			}
-			logger.Info("Successfully created record with nested data, ID: %v", result.ID)
-			h.sendResponseWithOptions(w, result.Data, nil, &options)
-			return
-		}
-	}
-
 	// Execute BeforeCreate hooks
 	hookCtx := &HookContext{
 		Context:   ctx,
@@ -622,172 +606,135 @@ func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, dat
 	// Use potentially modified data from hook context
 	data = hookCtx.Data
 
-	// Handle batch creation
+	// Normalize data to slice for unified processing
-	dataValue := reflect.ValueOf(data)
+	dataSlice := h.normalizeToSlice(data)
-	if dataValue.Kind() == reflect.Slice || dataValue.Kind() == reflect.Array {
+	logger.Debug("Processing %d item(s) for creation", len(dataSlice))
-		logger.Debug("Batch creation detected, count: %d", dataValue.Len())
 
-		// Check if any item needs nested processing
+	// Store original data maps for merging later
-		hasNestedData := false
+	originalDataMaps := make([]map[string]interface{}, 0, len(dataSlice))
-		for i := 0; i < dataValue.Len(); i++ {
-			item := dataValue.Index(i).Interface()
-			if itemMap, ok := item.(map[string]interface{}); ok {
-				if h.shouldUseNestedProcessor(itemMap, model) {
-					hasNestedData = true
-					break
-				}
-			}
-		}
 
-		if hasNestedData {
+	// Process all items in a transaction
-			logger.Info("Using nested CUD processor for batch create with nested data")
+	results := make([]interface{}, 0, len(dataSlice))
-			results := make([]interface{}, 0, dataValue.Len())
+	err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
-			err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
+		// Create temporary nested processor with transaction
-				// Temporarily swap the database to use transaction
+		txNestedProcessor := common.NewNestedCUDProcessor(tx, h.registry, h)
-				originalDB := h.nestedProcessor
-				h.nestedProcessor = common.NewNestedCUDProcessor(tx, h.registry, h)
-				defer func() {
-					h.nestedProcessor = originalDB
-				}()
 
-				for i := 0; i < dataValue.Len(); i++ {
+		for i, item := range dataSlice {
-					item := dataValue.Index(i).Interface()
+			itemMap, ok := item.(map[string]interface{})
-					if itemMap, ok := item.(map[string]interface{}); ok {
+			if !ok {
-						result, err := h.nestedProcessor.ProcessNestedCUD(ctx, "insert", itemMap, model, make(map[string]interface{}), tableName)
+				// Convert to map if needed
-						if err != nil {
-							return fmt.Errorf("failed to process item: %w", err)
-						}
-						results = append(results, result.Data)
-					}
-				}
-				return nil
-			})
-			if err != nil {
-				logger.Error("Error creating records with nested data: %v", err)
-				h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records with nested data", err)
-				return
-			}
-
-			// Execute AfterCreate hooks
-			hookCtx.Result = map[string]interface{}{"created": len(results), "data": results}
-			hookCtx.Error = nil
-
-			if err := h.hooks.Execute(AfterCreate, hookCtx); err != nil {
-				logger.Error("AfterCreate hook failed: %v", err)
-				h.sendError(w, http.StatusInternalServerError, "hook_error", "Hook execution failed", err)
-				return
-			}
-
-			logger.Info("Successfully created %d records with nested data", len(results))
-			h.sendResponseWithOptions(w, results, nil, &options)
-			return
-		}
-
-		// Standard batch insert without nested relations
-		// Use transaction for batch insert
-		err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
-			for i := 0; i < dataValue.Len(); i++ {
-				item := dataValue.Index(i).Interface()
-
-				// Convert item to model type - create a pointer to the model
-				modelValue := reflect.New(reflect.TypeOf(model)).Interface()
 				jsonData, err := json.Marshal(item)
 				if err != nil {
-					return fmt.Errorf("failed to marshal item: %w", err)
+					return fmt.Errorf("failed to marshal item %d: %w", i, err)
 				}
-				if err := json.Unmarshal(jsonData, modelValue); err != nil {
+				itemMap = make(map[string]interface{})
-					return fmt.Errorf("failed to unmarshal item: %w", err)
+				if err := json.Unmarshal(jsonData, &itemMap); err != nil {
-				}
+					return fmt.Errorf("failed to unmarshal item %d: %w", i, err)
-
-				query := tx.NewInsert().Model(modelValue).Table(tableName)
-
-				// Execute BeforeScan hooks - pass query chain so hooks can modify it
-				batchHookCtx := &HookContext{
-					Context:   ctx,
-					Handler:   h,
-					Schema:    schema,
-					Entity:    entity,
-					TableName: tableName,
-					Model:     model,
-					Options:   options,
-					Data:      modelValue,
-					Writer:    w,
-					Query:     query,
-				}
-				if err := h.hooks.Execute(BeforeScan, batchHookCtx); err != nil {
-					return fmt.Errorf("BeforeScan hook failed: %w", err)
-				}
-
-				// Use potentially modified query from hook context
-				if modifiedQuery, ok := batchHookCtx.Query.(common.InsertQuery); ok {
-					query = modifiedQuery
-				}
-
-				if _, err := query.Exec(ctx); err != nil {
-					return fmt.Errorf("failed to insert record: %w", err)
 				}
 			}
-			return nil
-		})
 
-		if err != nil {
+			// Store a copy of the original data map for merging later
-			logger.Error("Error creating records: %v", err)
+			originalMap := make(map[string]interface{})
-			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", err)
+			for k, v := range itemMap {
-			return
+				originalMap[k] = v
+			}
+			originalDataMaps = append(originalDataMaps, originalMap)
+
+			// Extract nested relations if present (but don't process them yet)
+			var nestedRelations map[string]interface{}
+			if h.shouldUseNestedProcessor(itemMap, model) {
+				logger.Debug("Extracting nested relations for item %d", i)
+				cleanedData, relations, err := h.extractNestedRelations(itemMap, model)
+				if err != nil {
+					return fmt.Errorf("failed to extract nested relations for item %d: %w", i, err)
+				}
+				itemMap = cleanedData
+				nestedRelations = relations
+			}
+
+			// Convert item to model type - create a pointer to the model
+			modelValue := reflect.New(reflect.TypeOf(model)).Interface()
+			jsonData, err := json.Marshal(itemMap)
+			if err != nil {
+				return fmt.Errorf("failed to marshal item %d: %w", i, err)
+			}
+			if err := json.Unmarshal(jsonData, modelValue); err != nil {
+				return fmt.Errorf("failed to unmarshal item %d: %w", i, err)
+			}
+
+			// Create insert query
+			query := tx.NewInsert().Model(modelValue).Table(tableName).Returning("*")
+
+			// Execute BeforeScan hooks - pass query chain so hooks can modify it
+			itemHookCtx := &HookContext{
+				Context:   ctx,
+				Handler:   h,
+				Schema:    schema,
+				Entity:    entity,
+				TableName: tableName,
+				Model:     model,
+				Options:   options,
+				Data:      modelValue,
+				Writer:    w,
+				Query:     query,
+			}
+			if err := h.hooks.Execute(BeforeScan, itemHookCtx); err != nil {
+				return fmt.Errorf("BeforeScan hook failed for item %d: %w", i, err)
+			}
+
+			// Use potentially modified query from hook context
+			if modifiedQuery, ok := itemHookCtx.Query.(common.InsertQuery); ok {
+				query = modifiedQuery
+			}
+
+			// Execute insert and get the ID
+			if _, err := query.Exec(ctx); err != nil {
+				return fmt.Errorf("failed to insert item %d: %w", i, err)
+			}
+
+			// Get the inserted ID
+			insertedID := reflection.GetPrimaryKeyValue(modelValue)
+
+			// Now process nested relations with the parent ID
+			if len(nestedRelations) > 0 {
+				logger.Debug("Processing nested relations for item %d with parent ID: %v", i, insertedID)
+				if err := h.processChildRelationsWithParentID(ctx, txNestedProcessor, "insert", nestedRelations, model, insertedID); err != nil {
+					return fmt.Errorf("failed to process nested relations for item %d: %w", i, err)
+				}
+			}
+
+			results = append(results, modelValue)
 		}
+		return nil
+	})
 
-		// Execute AfterCreate hooks for batch creation
-		hookCtx.Result = map[string]interface{}{"created": dataValue.Len()}
-		hookCtx.Error = nil
-
-		if err := h.hooks.Execute(AfterCreate, hookCtx); err != nil {
-			logger.Error("AfterCreate hook failed: %v", err)
-			h.sendError(w, http.StatusInternalServerError, "hook_error", "Hook execution failed", err)
-			return
-		}
-
-		h.sendResponse(w, map[string]interface{}{"created": dataValue.Len()}, nil)
-		return
-	}
-
-	// Single record creation - create a pointer to the model
-	modelValue := reflect.New(reflect.TypeOf(model)).Interface()
-	jsonData, err := json.Marshal(data)
 	if err != nil {
-		logger.Error("Error marshaling data: %v", err)
+		logger.Error("Error creating records: %v", err)
-		h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
+		h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", err)
-		return
-	}
-	if err := json.Unmarshal(jsonData, modelValue); err != nil {
-		logger.Error("Error unmarshaling data: %v", err)
-		h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
 		return
 	}
 
-	query := h.db.NewInsert().Model(modelValue).Table(tableName)
+	// Merge created records with original request data
-
+	// This preserves extra keys from the request
-	// Execute BeforeScan hooks - pass query chain so hooks can modify it
+	mergedResults := make([]interface{}, 0, len(results))
-	hookCtx.Data = modelValue
+	for i, result := range results {
-	hookCtx.Query = query
+		if i < len(originalDataMaps) {
-	if err := h.hooks.Execute(BeforeScan, hookCtx); err != nil {
+			merged := h.mergeRecordWithRequest(result, originalDataMaps[i])
-		logger.Error("BeforeScan hook failed: %v", err)
+			mergedResults = append(mergedResults, merged)
-		h.sendError(w, http.StatusBadRequest, "hook_error", "Hook execution failed", err)
+		} else {
-		return
+			mergedResults = append(mergedResults, result)
+		}
 	}
 
-	// Use potentially modified query from hook context
+	// Execute AfterCreate hooks
-	if modifiedQuery, ok := hookCtx.Query.(common.InsertQuery); ok {
+	var responseData interface{}
-		query = modifiedQuery
+	if len(mergedResults) == 1 {
+		responseData = mergedResults[0]
+		hookCtx.Result = mergedResults[0]
+	} else {
+		responseData = mergedResults
+		hookCtx.Result = map[string]interface{}{"created": len(mergedResults), "data": mergedResults}
 	}
-
-	if _, err := query.Exec(ctx); err != nil {
-		logger.Error("Error creating record: %v", err)
-		h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating record", err)
-		return
-	}
-
-	// Execute AfterCreate hooks for single record creation
-	hookCtx.Result = modelValue
 	hookCtx.Error = nil
 
 	if err := h.hooks.Execute(AfterCreate, hookCtx); err != nil {
@@ -796,7 +743,8 @@ func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, dat
 		return
 	}
 
-	h.sendResponseWithOptions(w, modelValue, nil, &options)
+	logger.Info("Successfully created %d record(s)", len(mergedResults))
+	h.sendResponseWithOptions(w, responseData, nil, &options)
 }
 
 func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id string, idPtr *int64, data interface{}, options ExtendedRequestOptions) {
@@ -814,46 +762,6 @@ func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id
 
 	logger.Info("Updating record in %s.%s", schema, entity)
 
-	// Convert data to map first for nested processor check
-	dataMap, ok := data.(map[string]interface{})
-	if !ok {
-		jsonData, err := json.Marshal(data)
-		if err != nil {
-			logger.Error("Error marshaling data: %v", err)
-			h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
-			return
-		}
-		if err := json.Unmarshal(jsonData, &dataMap); err != nil {
-			logger.Error("Error unmarshaling data: %v", err)
-			h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
-			return
-		}
-	}
-
-	// Check if we should use nested processing
-	if h.shouldUseNestedProcessor(dataMap, model) {
-		logger.Info("Using nested CUD processor for update operation")
-		// Ensure ID is in the data map
-		var targetID interface{}
-		if id != "" {
-			targetID = id
-		} else if idPtr != nil {
-			targetID = *idPtr
-		}
-		if targetID != nil {
-			dataMap["id"] = targetID
-		}
-		result, err := h.nestedProcessor.ProcessNestedCUD(ctx, "update", dataMap, model, make(map[string]interface{}), tableName)
-		if err != nil {
-			logger.Error("Error in nested update: %v", err)
-			h.sendError(w, http.StatusInternalServerError, "update_error", "Error updating record with nested data", err)
-			return
-		}
-		logger.Info("Successfully updated record with nested data, rows: %d", result.AffectedRows)
-		h.sendResponseWithOptions(w, result.Data, nil, &options)
-		return
-	}
-
 	// Execute BeforeUpdate hooks
 	hookCtx := &HookContext{
 		Context:   ctx,
@@ -877,8 +785,8 @@ func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id
 	// Use potentially modified data from hook context
 	data = hookCtx.Data
 
-	// Convert data to map (again if modified by hooks)
+	// Convert data to map
-	dataMap, ok = data.(map[string]interface{})
+	dataMap, ok := data.(map[string]interface{})
 	if !ok {
 		jsonData, err := json.Marshal(data)
 		if err != nil {
@@ -893,53 +801,108 @@ func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id
 		}
 	}
 
-	query := h.db.NewUpdate().Table(tableName).SetMap(dataMap)
+	// Determine target ID
-	pkName := reflection.GetPrimaryKeyName(model)
+	var targetID interface{}
-	// Apply ID filter
+	if id != "" {
-	switch {
+		targetID = id
-	case id != "":
+	} else if idPtr != nil {
-		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), id)
+		targetID = *idPtr
-	case idPtr != nil:
+	} else {
-		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), *idPtr)
-	default:
 		h.sendError(w, http.StatusBadRequest, "missing_id", "ID is required for update", nil)
 		return
 	}
 
-	// Execute BeforeScan hooks - pass query chain so hooks can modify it
+	// Get the primary key name for the model
-	hookCtx.Query = query
+	pkName := reflection.GetPrimaryKeyName(model)
-	if err := h.hooks.Execute(BeforeScan, hookCtx); err != nil {
-		logger.Error("BeforeScan hook failed: %v", err)
-		h.sendError(w, http.StatusBadRequest, "hook_error", "Hook execution failed", err)
-		return
-	}
 
-	// Use potentially modified query from hook context
+	// Variable to store the updated record
-	if modifiedQuery, ok := hookCtx.Query.(common.UpdateQuery); ok {
+	var updatedRecord interface{}
-		query = modifiedQuery
+
-	}
+	// Process nested relations if present
+	err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
+		// Create temporary nested processor with transaction
+		txNestedProcessor := common.NewNestedCUDProcessor(tx, h.registry, h)
+
+		// Extract nested relations if present (but don't process them yet)
+		var nestedRelations map[string]interface{}
+		if h.shouldUseNestedProcessor(dataMap, model) {
+			logger.Debug("Extracting nested relations for update")
+			cleanedData, relations, err := h.extractNestedRelations(dataMap, model)
+			if err != nil {
+				return fmt.Errorf("failed to extract nested relations: %w", err)
+			}
+			dataMap = cleanedData
+			nestedRelations = relations
+		}
+
+		// Ensure ID is in the data map for the update
+		dataMap[pkName] = targetID
+
+		// Create update query
+		query := tx.NewUpdate().Table(tableName).SetMap(dataMap)
+		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), targetID)
+
+		// Execute BeforeScan hooks - pass query chain so hooks can modify it
+		hookCtx.Query = query
+		if err := h.hooks.Execute(BeforeScan, hookCtx); err != nil {
+			return fmt.Errorf("BeforeScan hook failed: %w", err)
+		}
+
+		// Use potentially modified query from hook context
+		if modifiedQuery, ok := hookCtx.Query.(common.UpdateQuery); ok {
+			query = modifiedQuery
+		}
+
+		// Execute update
+		result, err := query.Exec(ctx)
+		if err != nil {
+			return fmt.Errorf("failed to update record: %w", err)
+		}
+
+		// Now process nested relations with the parent ID
+		if len(nestedRelations) > 0 {
+			logger.Debug("Processing nested relations for update with parent ID: %v", targetID)
+			if err := h.processChildRelationsWithParentID(ctx, txNestedProcessor, "update", nestedRelations, model, targetID); err != nil {
+				return fmt.Errorf("failed to process nested relations: %w", err)
+			}
+		}
+
+		// Fetch the updated record to return the new values
+		modelValue := reflect.New(reflect.TypeOf(model)).Interface()
+		selectQuery := tx.NewSelect().Model(modelValue).Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), targetID)
+		if err := selectQuery.ScanModel(ctx); err != nil {
+			return fmt.Errorf("failed to fetch updated record: %w", err)
+		}
+
+		updatedRecord = modelValue
+
+		// Store result for hooks
+		hookCtx.Result = updatedRecord
+		_ = result // Keep result variable for potential future use
+		return nil
+	})
 
-	result, err := query.Exec(ctx)
 	if err != nil {
 		logger.Error("Error updating record: %v", err)
 		h.sendError(w, http.StatusInternalServerError, "update_error", "Error updating record", err)
 		return
 	}
 
-	// Execute AfterUpdate hooks
+	// Merge the updated record with the original request data
-	responseData := map[string]interface{}{
+	// This preserves extra keys from the request and updates values from the database
-		"updated": result.RowsAffected(),
+	mergedData := h.mergeRecordWithRequest(updatedRecord, dataMap)
-	}
-	hookCtx.Result = responseData
-	hookCtx.Error = nil
 
+	// Execute AfterUpdate hooks
+	hookCtx.Result = mergedData
+	hookCtx.Error = nil
 	if err := h.hooks.Execute(AfterUpdate, hookCtx); err != nil {
 		logger.Error("AfterUpdate hook failed: %v", err)
 		h.sendError(w, http.StatusInternalServerError, "hook_error", "Hook execution failed", err)
 		return
 	}
 
-	h.sendResponseWithOptions(w, responseData, nil, &options)
+	logger.Info("Successfully updated record with ID: %v", targetID)
+	h.sendResponseWithOptions(w, mergedData, nil, &options)
 }
 
 func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id string, data interface{}) {
@@ -1013,6 +976,7 @@ func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id
 			// Array of IDs or objects with ID field
 			logger.Info("Batch delete with %d items ([]interface{})", len(v))
 			deletedCount := 0
+			pkName := reflection.GetPrimaryKeyName(model)
 			err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
 				for _, item := range v {
 					var itemID interface{}
@@ -1022,7 +986,7 @@ func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id
 					case string:
 						itemID = v
 					case map[string]interface{}:
-						itemID = v["id"]
+						itemID = v[pkName]
 					default:
 						itemID = item
 					}
@@ -1079,9 +1043,10 @@ func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id
 			// Array of objects with id field
 			logger.Info("Batch delete with %d items ([]map[string]interface{})", len(v))
 			deletedCount := 0
+			pkName := reflection.GetPrimaryKeyName(model)
 			err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
 				for _, item := range v {
-					if itemID, ok := item["id"]; ok && itemID != nil {
+					if itemID, ok := item[pkName]; ok && itemID != nil {
 						itemIDStr := fmt.Sprintf("%v", itemID)
 
 						// Execute hooks for each item
@@ -1129,7 +1094,8 @@ func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id
 
 		case map[string]interface{}:
 			// Single object with id field
-			if itemID, ok := v["id"]; ok && itemID != nil {
+			pkName := reflection.GetPrimaryKeyName(model)
+			if itemID, ok := v[pkName]; ok && itemID != nil {
 				id = fmt.Sprintf("%v", itemID)
 			}
 		}
@@ -1199,6 +1165,229 @@ func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id
 	h.sendResponse(w, responseData, nil)
 }
 
+// mergeRecordWithRequest merges a database record with the original request data
+// This preserves extra keys from the request that aren't in the database model
+// and updates values from the database (e.g., from SQL triggers or defaults)
+func (h *Handler) mergeRecordWithRequest(dbRecord interface{}, requestData map[string]interface{}) map[string]interface{} {
+	// Convert the database record to a map
+	dbMap := make(map[string]interface{})
+
+	// Marshal and unmarshal to convert struct to map
+	jsonData, err := json.Marshal(dbRecord)
+	if err != nil {
+		logger.Warn("Failed to marshal database record for merging: %v", err)
+		return requestData
+	}
+
+	if err := json.Unmarshal(jsonData, &dbMap); err != nil {
+		logger.Warn("Failed to unmarshal database record for merging: %v", err)
+		return requestData
+	}
+
+	// Start with the request data (preserves extra keys)
+	result := make(map[string]interface{})
+	for k, v := range requestData {
+		result[k] = v
+	}
+
+	// Update with values from database (overwrites with DB values, including trigger changes)
+	for k, v := range dbMap {
+		result[k] = v
+	}
+
+	return result
+}
+
+// normalizeToSlice converts data to a slice. Single items become a 1-item slice.
+func (h *Handler) normalizeToSlice(data interface{}) []interface{} {
+	if data == nil {
+		return []interface{}{}
+	}
+
+	dataValue := reflect.ValueOf(data)
+	if dataValue.Kind() == reflect.Slice || dataValue.Kind() == reflect.Array {
+		result := make([]interface{}, dataValue.Len())
+		for i := 0; i < dataValue.Len(); i++ {
+			result[i] = dataValue.Index(i).Interface()
+		}
+		return result
+	}
+
+	// Single item - return as 1-item slice
+	return []interface{}{data}
+}
+
+// extractNestedRelations extracts nested relations from data, returning cleaned data and relations
+// This does NOT process the relations, just separates them for later processing
+func (h *Handler) extractNestedRelations(
+	data map[string]interface{},
+	model interface{},
+) (map[string]interface{}, map[string]interface{}, error) {
+	// Get model type for reflection
+	modelType := reflect.TypeOf(model)
+	for modelType != nil && (modelType.Kind() == reflect.Ptr || modelType.Kind() == reflect.Slice || modelType.Kind() == reflect.Array) {
+		modelType = modelType.Elem()
+	}
+
+	if modelType == nil || modelType.Kind() != reflect.Struct {
+		return data, nil, fmt.Errorf("model must be a struct type, got %v", modelType)
+	}
+
+	// Separate relation fields from regular fields
+	cleanedData := make(map[string]interface{})
+	relations := make(map[string]interface{})
+
+	for key, value := range data {
+		// Skip _request field
+		if key == "_request" {
+			continue
+		}
+
+		// Check if this field is a relation
+		relInfo := h.GetRelationshipInfo(modelType, key)
+		if relInfo != nil {
+			logger.Debug("Found nested relation field: %s (type: %s)", key, relInfo.RelationType)
+			relations[key] = value
+		} else {
+			cleanedData[key] = value
+		}
+	}
+
+	return cleanedData, relations, nil
+}
+
+// processChildRelationsWithParentID processes nested relations with a parent ID
+func (h *Handler) processChildRelationsWithParentID(
+	ctx context.Context,
+	processor *common.NestedCUDProcessor,
+	operation string,
+	relations map[string]interface{},
+	parentModel interface{},
+	parentID interface{},
+) error {
+	// Get model type for reflection
+	modelType := reflect.TypeOf(parentModel)
+	for modelType != nil && (modelType.Kind() == reflect.Ptr || modelType.Kind() == reflect.Slice || modelType.Kind() == reflect.Array) {
+		modelType = modelType.Elem()
+	}
+
+	if modelType == nil || modelType.Kind() != reflect.Struct {
+		return fmt.Errorf("model must be a struct type, got %v", modelType)
+	}
+
+	// Process each relation
+	for relationName, relationValue := range relations {
+		if relationValue == nil {
+			continue
+		}
+
+		// Get relationship info
+		relInfo := h.GetRelationshipInfo(modelType, relationName)
+		if relInfo == nil {
+			logger.Warn("No relationship info found for %s, skipping", relationName)
+			continue
+		}
+
+		// Process this relation with parent ID
+		if err := h.processChildRelationsForField(ctx, processor, operation, relationName, relationValue, relInfo, modelType, parentID); err != nil {
+			return fmt.Errorf("failed to process relation %s: %w", relationName, err)
+		}
+	}
+
+	return nil
+}
+
+// processChildRelationsForField processes a single nested relation field
+func (h *Handler) processChildRelationsForField(
+	ctx context.Context,
+	processor *common.NestedCUDProcessor,
+	operation string,
+	relationName string,
+	relationValue interface{},
+	relInfo *common.RelationshipInfo,
+	parentModelType reflect.Type,
+	parentID interface{},
+) error {
+	if relationValue == nil {
+		return nil
+	}
+
+	// Get the related model
+	field, found := parentModelType.FieldByName(relInfo.FieldName)
+	if !found {
+		return fmt.Errorf("field %s not found in model", relInfo.FieldName)
+	}
+
+	// Get the model type for the relation
+	relatedModelType := field.Type
+	if relatedModelType.Kind() == reflect.Slice {
+		relatedModelType = relatedModelType.Elem()
+	}
+	if relatedModelType.Kind() == reflect.Ptr {
+		relatedModelType = relatedModelType.Elem()
+	}
+
+	// Create an instance of the related model
+	relatedModel := reflect.New(relatedModelType).Elem().Interface()
+
+	// Get table name for related model
+	relatedTableName := h.getTableNameForRelatedModel(relatedModel, relInfo.JSONName)
+
+	// Prepare parent IDs for foreign key injection
+	parentIDs := make(map[string]interface{})
+	if relInfo.ForeignKey != "" && parentID != nil {
+		baseName := strings.TrimSuffix(relInfo.ForeignKey, "ID")
+		baseName = strings.TrimSuffix(strings.ToLower(baseName), "_id")
+		parentIDs[baseName] = parentID
+	}
+
+	// Process based on relation type and data structure
+	switch v := relationValue.(type) {
+	case map[string]interface{}:
+		// Single related object
+		_, err := processor.ProcessNestedCUD(ctx, operation, v, relatedModel, parentIDs, relatedTableName)
+		if err != nil {
+			return fmt.Errorf("failed to process single relation: %w", err)
+		}
+
+	case []interface{}:
+		// Multiple related objects
+		for i, item := range v {
+			if itemMap, ok := item.(map[string]interface{}); ok {
+				_, err := processor.ProcessNestedCUD(ctx, operation, itemMap, relatedModel, parentIDs, relatedTableName)
+				if err != nil {
+					return fmt.Errorf("failed to process relation item %d: %w", i, err)
+				}
+			}
+		}
+
+	case []map[string]interface{}:
+		// Multiple related objects (typed slice)
+		for i, itemMap := range v {
+			_, err := processor.ProcessNestedCUD(ctx, operation, itemMap, relatedModel, parentIDs, relatedTableName)
+			if err != nil {
+				return fmt.Errorf("failed to process relation item %d: %w", i, err)
+			}
+		}
+
+	default:
+		return fmt.Errorf("unsupported relation data type: %T", relationValue)
+	}
+
+	return nil
+}
+
+// getTableNameForRelatedModel gets the table name for a related model
+func (h *Handler) getTableNameForRelatedModel(model interface{}, defaultName string) string {
+	if provider, ok := model.(common.TableNameProvider); ok {
+		tableName := provider.TableName()
+		if tableName != "" {
+			return tableName
+		}
+	}
+	return defaultName
+}
+
 // qualifyColumnName ensures column name is fully qualified with table name if not already
 func (h *Handler) qualifyColumnName(columnName, fullTableName string) string {
 	// Check if column already has a table/schema prefix (contains a dot)
@@ -1545,22 +1734,22 @@ func (h *Handler) cleanJSON(data interface{}) interface{} {
 }
 
 func (h *Handler) sendError(w common.ResponseWriter, statusCode int, code, message string, err error) {
-	var details string
+	var errorMsg string
 	if err != nil {
-		details = err.Error()
+		errorMsg = err.Error()
+	} else if message != "" {
+		errorMsg = message
+	} else {
+		errorMsg = code
 	}
 
-	response := common.Response{
+	response := map[string]interface{}{
-		Success: false,
+		"_error":  errorMsg,
-		Error: &common.APIError{
+		"_retval": 1,
-			Code:    code,
-			Message: message,
-			Details: details,
-		},
 	}
 	w.WriteHeader(statusCode)
-	if err := w.WriteJSON(response); err != nil {
+	if jsonErr := w.WriteJSON(response); jsonErr != nil {
-		logger.Error("Failed to write JSON error response: %v", err)
+		logger.Error("Failed to write JSON error response: %v", jsonErr)
 	}
 }
 
@@ -1791,7 +1980,8 @@ func filterExtendedOptions(validator *common.ColumnValidator, options ExtendedRe
 }
 
 // shouldUseNestedProcessor determines if we should use nested CUD processing
-// It checks if the data contains nested relations or a _request field
+// It recursively checks if the data contains deeply nested relations or _request fields
+// Simple one-level relations without further nesting don't require the nested processor
 func (h *Handler) shouldUseNestedProcessor(data map[string]interface{}, model interface{}) bool {
 	return common.ShouldUseNestedProcessor(data, model, h)
 }
@@ -1853,12 +2043,40 @@ func (h *Handler) getRelationshipInfo(modelType reflect.Type, relationName strin
 				// Determine if it's belongsTo or hasMany/hasOne
 				if field.Type.Kind() == reflect.Slice {
 					info.relationType = "hasMany"
+					// Get the element type for slice
+					elemType := field.Type.Elem()
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.relatedModel = reflect.New(elemType).Elem().Interface()
+					}
 				} else if field.Type.Kind() == reflect.Ptr || field.Type.Kind() == reflect.Struct {
 					info.relationType = "belongsTo"
+					elemType := field.Type
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.relatedModel = reflect.New(elemType).Elem().Interface()
+					}
 				}
 			} else if strings.Contains(gormTag, "many2many") {
 				info.relationType = "many2many"
 				info.joinTable = h.extractTagValue(gormTag, "many2many")
+				// Get the element type for many2many (always slice)
+				if field.Type.Kind() == reflect.Slice {
+					elemType := field.Type.Elem()
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.relatedModel = reflect.New(elemType).Elem().Interface()
+					}
+				}
+			} else {
+				// Field has no GORM relationship tags, so it's not a relation
+				return nil
 			}
 
 			return info

pkg/restheadspec/handler_nested_test.go

@@ -0,0 +1,423 @@
+package restheadspec
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+// Test models for nested CRUD operations
+type TestUser struct {
+	ID    int64      `json:"id" bun:"id,pk,autoincrement"`
+	Name  string     `json:"name"`
+	Posts []TestPost `json:"posts" gorm:"foreignKey:UserID"`
+}
+
+type TestPost struct {
+	ID       int64         `json:"id" bun:"id,pk,autoincrement"`
+	UserID   int64         `json:"user_id"`
+	Title    string        `json:"title"`
+	Comments []TestComment `json:"comments" gorm:"foreignKey:PostID"`
+}
+
+type TestComment struct {
+	ID      int64  `json:"id" bun:"id,pk,autoincrement"`
+	PostID  int64  `json:"post_id"`
+	Content string `json:"content"`
+}
+
+func (TestUser) TableName() string    { return "users" }
+func (TestPost) TableName() string    { return "posts" }
+func (TestComment) TableName() string { return "comments" }
+
+// Test extractNestedRelations function
+func TestExtractNestedRelations(t *testing.T) {
+	// Create handler
+	registry := &mockRegistry{
+		models: map[string]interface{}{
+			"users":    TestUser{},
+			"posts":    TestPost{},
+			"comments": TestComment{},
+		},
+	}
+	handler := NewHandler(nil, registry)
+
+	tests := []struct {
+		name               string
+		data               map[string]interface{}
+		model              interface{}
+		expectedCleanCount int
+		expectedRelCount   int
+	}{
+		{
+			name: "User with posts",
+			data: map[string]interface{}{
+				"name": "John Doe",
+				"posts": []map[string]interface{}{
+					{"title": "Post 1"},
+				},
+			},
+			model:              TestUser{},
+			expectedCleanCount: 1, // name
+			expectedRelCount:   1, // posts
+		},
+		{
+			name: "Post with comments",
+			data: map[string]interface{}{
+				"title": "Test Post",
+				"comments": []map[string]interface{}{
+					{"content": "Comment 1"},
+					{"content": "Comment 2"},
+				},
+			},
+			model:              TestPost{},
+			expectedCleanCount: 1, // title
+			expectedRelCount:   1, // comments
+		},
+		{
+			name: "User with nested posts and comments",
+			data: map[string]interface{}{
+				"name": "Jane Doe",
+				"posts": []map[string]interface{}{
+					{
+						"title": "Post 1",
+						"comments": []map[string]interface{}{
+							{"content": "Comment 1"},
+						},
+					},
+				},
+			},
+			model:              TestUser{},
+			expectedCleanCount: 1, // name
+			expectedRelCount:   1, // posts (which contains nested comments)
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cleanedData, relations, err := handler.extractNestedRelations(tt.data, tt.model)
+			if err != nil {
+				t.Errorf("extractNestedRelations() error = %v", err)
+				return
+			}
+
+			if len(cleanedData) != tt.expectedCleanCount {
+				t.Errorf("Expected %d cleaned fields, got %d: %+v", tt.expectedCleanCount, len(cleanedData), cleanedData)
+			}
+
+			if len(relations) != tt.expectedRelCount {
+				t.Errorf("Expected %d relation fields, got %d: %+v", tt.expectedRelCount, len(relations), relations)
+			}
+
+			t.Logf("Cleaned data: %+v", cleanedData)
+			t.Logf("Relations: %+v", relations)
+		})
+	}
+}
+
+// Test shouldUseNestedProcessor function
+func TestShouldUseNestedProcessor(t *testing.T) {
+	registry := &mockRegistry{
+		models: map[string]interface{}{
+			"users": TestUser{},
+			"posts": TestPost{},
+		},
+	}
+	handler := NewHandler(nil, registry)
+
+	tests := []struct {
+		name     string
+		data     map[string]interface{}
+		model    interface{}
+		expected bool
+	}{
+		{
+			name: "Data with simple nested posts (no further nesting)",
+			data: map[string]interface{}{
+				"name": "John",
+				"posts": []map[string]interface{}{
+					{"title": "Post 1"},
+				},
+			},
+			model:    TestUser{},
+			expected: false, // Simple one-level nesting doesn't require nested processor
+		},
+		{
+			name: "Data with deeply nested relations",
+			data: map[string]interface{}{
+				"name": "John",
+				"posts": []map[string]interface{}{
+					{
+						"title": "Post 1",
+						"comments": []map[string]interface{}{
+							{"content": "Comment 1"},
+						},
+					},
+				},
+			},
+			model:    TestUser{},
+			expected: true, // Multi-level nesting requires nested processor
+		},
+		{
+			name: "Data without nested relations",
+			data: map[string]interface{}{
+				"name": "John",
+			},
+			model:    TestUser{},
+			expected: false,
+		},
+		{
+			name: "Data with _request field",
+			data: map[string]interface{}{
+				"_request": "insert",
+				"name":     "John",
+			},
+			model:    TestUser{},
+			expected: true,
+		},
+		{
+			name: "Nested data with _request field",
+			data: map[string]interface{}{
+				"name": "John",
+				"posts": []map[string]interface{}{
+					{
+						"_request": "insert",
+						"title":    "Post 1",
+					},
+				},
+			},
+			model:    TestUser{},
+			expected: true, // _request at nested level requires nested processor
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := handler.shouldUseNestedProcessor(tt.data, tt.model)
+			if result != tt.expected {
+				t.Errorf("shouldUseNestedProcessor() = %v, expected %v", result, tt.expected)
+			}
+		})
+	}
+}
+
+// Test normalizeToSlice function
+func TestNormalizeToSlice(t *testing.T) {
+	registry := &mockRegistry{}
+	handler := NewHandler(nil, registry)
+
+	tests := []struct {
+		name     string
+		input    interface{}
+		expected int // expected slice length
+	}{
+		{
+			name:     "Single object",
+			input:    map[string]interface{}{"name": "John"},
+			expected: 1,
+		},
+		{
+			name: "Slice of objects",
+			input: []map[string]interface{}{
+				{"name": "John"},
+				{"name": "Jane"},
+			},
+			expected: 2,
+		},
+		{
+			name: "Array of interfaces",
+			input: []interface{}{
+				map[string]interface{}{"name": "John"},
+				map[string]interface{}{"name": "Jane"},
+				map[string]interface{}{"name": "Bob"},
+			},
+			expected: 3,
+		},
+		{
+			name:     "Nil input",
+			input:    nil,
+			expected: 0,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := handler.normalizeToSlice(tt.input)
+			if len(result) != tt.expected {
+				t.Errorf("normalizeToSlice() returned slice of length %d, expected %d", len(result), tt.expected)
+			}
+		})
+	}
+}
+
+// Test GetRelationshipInfo function
+func TestGetRelationshipInfo(t *testing.T) {
+	registry := &mockRegistry{}
+	handler := NewHandler(nil, registry)
+
+	tests := []struct {
+		name         string
+		modelType    reflect.Type
+		relationName string
+		expectNil    bool
+	}{
+		{
+			name:         "User posts relation",
+			modelType:    reflect.TypeOf(TestUser{}),
+			relationName: "posts",
+			expectNil:    false,
+		},
+		{
+			name:         "Post comments relation",
+			modelType:    reflect.TypeOf(TestPost{}),
+			relationName: "comments",
+			expectNil:    false,
+		},
+		{
+			name:         "Non-existent relation",
+			modelType:    reflect.TypeOf(TestUser{}),
+			relationName: "nonexistent",
+			expectNil:    true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := handler.GetRelationshipInfo(tt.modelType, tt.relationName)
+			if tt.expectNil && result != nil {
+				t.Errorf("Expected nil, got %+v", result)
+			}
+			if !tt.expectNil && result == nil {
+				t.Errorf("Expected non-nil relationship info")
+			}
+			if result != nil {
+				t.Logf("Relationship info: FieldName=%s, JSONName=%s, RelationType=%s, ForeignKey=%s",
+					result.FieldName, result.JSONName, result.RelationType, result.ForeignKey)
+			}
+		})
+	}
+}
+
+// Mock registry for testing
+type mockRegistry struct {
+	models map[string]interface{}
+}
+
+func (m *mockRegistry) Register(name string, model interface{}) {
+	m.RegisterModel(name, model)
+}
+
+func (m *mockRegistry) RegisterModel(name string, model interface{}) error {
+	if m.models == nil {
+		m.models = make(map[string]interface{})
+	}
+	m.models[name] = model
+	return nil
+}
+
+func (m *mockRegistry) GetModelByEntity(schema, entity string) (interface{}, error) {
+	if model, ok := m.models[entity]; ok {
+		return model, nil
+	}
+	return nil, fmt.Errorf("model not found: %s", entity)
+}
+
+func (m *mockRegistry) GetModelByName(name string) (interface{}, error) {
+	if model, ok := m.models[name]; ok {
+		return model, nil
+	}
+	return nil, fmt.Errorf("model not found: %s", name)
+}
+
+func (m *mockRegistry) GetModel(name string) (interface{}, error) {
+	return m.GetModelByName(name)
+}
+
+func (m *mockRegistry) HasModel(schema, entity string) bool {
+	_, ok := m.models[entity]
+	return ok
+}
+
+func (m *mockRegistry) ListModels() []string {
+	models := make([]string, 0, len(m.models))
+	for name := range m.models {
+		models = append(models, name)
+	}
+	return models
+}
+
+func (m *mockRegistry) GetAllModels() map[string]interface{} {
+	return m.models
+}
+
+// TestMultiLevelRelationExtraction tests extracting deeply nested relations
+func TestMultiLevelRelationExtraction(t *testing.T) {
+	registry := &mockRegistry{
+		models: map[string]interface{}{
+			"users":    TestUser{},
+			"posts":    TestPost{},
+			"comments": TestComment{},
+		},
+	}
+	handler := NewHandler(nil, registry)
+
+	// Test data with 3 levels: User -> Posts -> Comments
+	testData := map[string]interface{}{
+		"name": "John Doe",
+		"posts": []map[string]interface{}{
+			{
+				"title": "First Post",
+				"comments": []map[string]interface{}{
+					{"content": "Great post!"},
+					{"content": "Thanks for sharing!"},
+				},
+			},
+			{
+				"title": "Second Post",
+				"comments": []map[string]interface{}{
+					{"content": "Interesting read"},
+				},
+			},
+		},
+	}
+
+	// Extract relations from user
+	cleanedData, relations, err := handler.extractNestedRelations(testData, TestUser{})
+	if err != nil {
+		t.Fatalf("Failed to extract relations: %v", err)
+	}
+
+	// Verify user data is cleaned
+	if len(cleanedData) != 1 || cleanedData["name"] != "John Doe" {
+		t.Errorf("Expected cleaned data to contain only name, got: %+v", cleanedData)
+	}
+
+	// Verify posts relation was extracted
+	if len(relations) != 1 {
+		t.Errorf("Expected 1 relation (posts), got %d", len(relations))
+	}
+
+	posts, ok := relations["posts"]
+	if !ok {
+		t.Fatal("Expected posts relation to be extracted")
+	}
+
+	// Verify posts is a slice with 2 items
+	postsSlice, ok := posts.([]map[string]interface{})
+	if !ok {
+		t.Fatalf("Expected posts to be []map[string]interface{}, got %T", posts)
+	}
+
+	if len(postsSlice) != 2 {
+		t.Errorf("Expected 2 posts, got %d", len(postsSlice))
+	}
+
+	// Verify first post has comments
+	if _, hasComments := postsSlice[0]["comments"]; !hasComments {
+		t.Error("Expected first post to have comments")
+	}
+
+	t.Logf("Successfully extracted multi-level nested relations")
+	t.Logf("Cleaned data: %+v", cleanedData)
+	t.Logf("Relations: %d posts with nested comments", len(postsSlice))
+}

pkg/restheadspec/rownumber_test.go

@@ -10,7 +10,7 @@ import (
 type TestModel struct {
 	ID        int64  `json:"id" bun:"id,pk"`
 	Name      string `json:"name" bun:"name"`
-	RowNumber int64  `json:"_rownumber,omitempty" gorm:"-" bun:"-"`
+	RowNumber int64  `json:"_rownumber,omitempty" gorm:"-" bun:",scanonly"`
 }
 
 func TestSetRowNumbersOnRecords(t *testing.T) {