feat(reflection): add IsEmptyValue helper; guard CUD ops against missing PK

Add reflection.IsEmptyValue to detect nil, empty string, and zero numbers.
Use it in recursive CUD processing to skip update/delete when the primary
key is absent, logging a warning instead of proceeding with an invalid operation.

pkg/common/recursive_crud.go

@@ -143,6 +143,10 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 
 	case "update", "change":
 		// Only perform update if we have data to update
+		if reflection.IsEmptyValue(data[pkName]) {
+			logger.Warn("Skipping update for %s - no primary key", tableName)
+			return result, nil
+		}
 		if hasData {
 			rows, err := p.processUpdate(ctx, regularData, tableName, data[pkName])
 			if err != nil {
@@ -171,10 +175,15 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 		}
 
 	case "delete":
+		if reflection.IsEmptyValue(data[pkName]) {
+			logger.Warn("Skipping delete for %s - no primary key", tableName)
+			return result, nil
+		}
+
 		// Process child relations first (for referential integrity)
 		if err := p.processChildRelations(ctx, "delete", data[pkName], relationFields, result.RelationData, modelType, parentIDs); err != nil {
 			logger.Error("Failed to process child relations before delete: table=%s, id=%v, relations=%+v, error=%v", tableName, data[pkName], relationFields, err)
-			return nil, nil
+			return nil, fmt.Errorf("failed to process child relations: %w", err)
 		}
 
 		rows, err := p.processDelete(ctx, tableName, data[pkName])

pkg/reflection/helpers.go

@@ -51,6 +51,31 @@ func ExtractTableNameOnly(fullName string) string {
 	return fullName[startIndex:]
 }
 
+// IsEmptyValue reports whether v is nil, an empty string, or a zero number.
+func IsEmptyValue(v any) bool {
+	if v == nil {
+		return true
+	}
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Ptr {
+		if rv.IsNil() {
+			return true
+		}
+		rv = rv.Elem()
+	}
+	switch rv.Kind() {
+	case reflect.String:
+		return rv.String() == ""
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return rv.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return rv.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return rv.Float() == 0
+	}
+	return false
+}
+
 // GetPointerElement returns the element type if the provided reflect.Type is a pointer.
 // If the type is a slice of pointers, it returns the element type of the pointer within the slice.
 // If neither condition is met, it returns the original type.