Fixes for CUD operations

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 +606,113 @@ func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, dat
 	// Use potentially modified data from hook context
 	data = hookCtx.Data
 
-	// Handle batch creation
-	dataValue := reflect.ValueOf(data)
-	if dataValue.Kind() == reflect.Slice || dataValue.Kind() == reflect.Array {
-		logger.Debug("Batch creation detected, count: %d", dataValue.Len())
+	// Normalize data to slice for unified processing
+	dataSlice := h.normalizeToSlice(data)
+	logger.Debug("Processing %d item(s) for creation", len(dataSlice))
 
-		// Check if any item needs nested processing
-		hasNestedData := false
-		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
-				}
-			}
-		}
+	// Process all items in a transaction
+	results := make([]interface{}, 0, len(dataSlice))
+	err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
+		// Create temporary nested processor with transaction
+		txNestedProcessor := common.NewNestedCUDProcessor(tx, h.registry, h)
 
-		if hasNestedData {
-			logger.Info("Using nested CUD processor for batch create with nested data")
-			results := make([]interface{}, 0, dataValue.Len())
-			err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
-				// Temporarily swap the database to use transaction
-				originalDB := h.nestedProcessor
-				h.nestedProcessor = common.NewNestedCUDProcessor(tx, h.registry, h)
-				defer func() {
-					h.nestedProcessor = originalDB
-				}()
-
-				for i := 0; i < dataValue.Len(); i++ {
-					item := dataValue.Index(i).Interface()
-					if itemMap, ok := item.(map[string]interface{}); ok {
-						result, err := h.nestedProcessor.ProcessNestedCUD(ctx, "insert", itemMap, model, make(map[string]interface{}), tableName)
-						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()
+		for i, item := range dataSlice {
+			itemMap, ok := item.(map[string]interface{})
+			if !ok {
+				// Convert to map if needed
 				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 {
-					return fmt.Errorf("failed to unmarshal item: %w", 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)
+				itemMap = make(map[string]interface{})
+				if err := json.Unmarshal(jsonData, &itemMap); err != nil {
+					return fmt.Errorf("failed to unmarshal item %d: %w", i, err)
 				}
 			}
-			return nil
-		})
 
-		if err != nil {
-			logger.Error("Error creating records: %v", err)
-			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", err)
-			return
+			// 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)
-		h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", 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)
+		logger.Error("Error creating records: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", err)
 		return
 	}
 
-	query := h.db.NewInsert().Model(modelValue).Table(tableName)
-
-	// Execute BeforeScan hooks - pass query chain so hooks can modify it
-	hookCtx.Data = modelValue
-	hookCtx.Query = query
-	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
+	// Execute AfterCreate hooks
+	var responseData interface{}
+	if len(results) == 1 {
+		responseData = results[0]
+		hookCtx.Result = results[0]
+	} else {
+		responseData = results
+		hookCtx.Result = map[string]interface{}{"created": len(results), "data": results}
 	}
-
-	// Use potentially modified query from hook context
-	if modifiedQuery, ok := hookCtx.Query.(common.InsertQuery); ok {
-		query = modifiedQuery
-	}
-
-	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 +721,8 @@ 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(results))
+	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 +740,6 @@ 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 +763,8 @@ 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)
-	dataMap, ok = data.(map[string]interface{})
+	// Convert data to map
+	dataMap, ok := data.(map[string]interface{})
 	if !ok {
 		jsonData, err := json.Marshal(data)
 		if err != nil {
@@ -893,33 +779,74 @@ func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id
 		}
 	}
 
-	query := h.db.NewUpdate().Table(tableName).SetMap(dataMap)
-	pkName := reflection.GetPrimaryKeyName(model)
-	// Apply ID filter
-	switch {
-	case id != "":
-		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), id)
-	case idPtr != nil:
-		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), *idPtr)
-	default:
+	// Determine target ID
+	var targetID interface{}
+	if id != "" {
+		targetID = id
+	} else if idPtr != nil {
+		targetID = *idPtr
+	} else {
 		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
-	hookCtx.Query = query
-	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
-	}
+	// 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)
 
-	// Use potentially modified query from hook context
-	if modifiedQuery, ok := hookCtx.Query.(common.UpdateQuery); ok {
-		query = modifiedQuery
-	}
+		// 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["id"] = targetID
+
+		// Create update query
+		query := tx.NewUpdate().Table(tableName).SetMap(dataMap)
+		pkName := reflection.GetPrimaryKeyName(model)
+		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)
+			}
+		}
+
+		// Store result for hooks
+		hookCtx.Result = map[string]interface{}{
+			"updated": result.RowsAffected(),
+		}
+		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)
@@ -927,19 +854,15 @@ func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id
 	}
 
 	// Execute AfterUpdate hooks
-	responseData := map[string]interface{}{
-		"updated": result.RowsAffected(),
-	}
-	hookCtx.Result = responseData
 	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, hookCtx.Result, nil, &options)
 }
 
 func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id string, data interface{}) {
@@ -1199,6 +1122,196 @@ func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, id
 	h.sendResponse(w, responseData, nil)
 }
 
+// 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)