Refactor self referencing m2m support

association.go

@@ -107,7 +107,7 @@ func (association *Association) Replace(values ...interface{}) *Association {
 			if sourcePrimaryKeys := scope.getColumnAsArray(sourceForeignFieldNames, scope.Value); len(sourcePrimaryKeys) > 0 {
 				newDB = newDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(sourcePrimaryKeys)), toQueryValues(sourcePrimaryKeys)...)
 
-				association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB, relationship))
+				association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB))
 			}
 		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
 			// has_one or has_many relations, set foreign key to be nil (TODO or delete them?)
@@ -173,7 +173,7 @@ func (association *Association) Delete(values ...interface{}) *Association {
 		sql := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(deletingPrimaryKeys))
 		newDB = newDB.Where(sql, toQueryValues(deletingPrimaryKeys)...)
 
-		association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB, relationship))
+		association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB))
 	} else {
 		var foreignKeyMap = map[string]interface{}{}
 		for _, foreignKey := range relationship.ForeignDBNames {

customize_column_test.go

@@ -282,22 +282,44 @@ func TestBelongsToWithPartialCustomizedColumn(t *testing.T) {
 
 type SelfReferencingUser struct {
 	gorm.Model
-	Friends []*SelfReferencingUser `gorm:"many2many:UserFriends;AssociationForeignKey:ID=friend_id"`
+	Name    string
+	Friends []*SelfReferencingUser `gorm:"many2many:UserFriends;association_jointable_foreignkey:friend_id"`
 }
 
 func TestSelfReferencingMany2ManyColumn(t *testing.T) {
 	DB.DropTable(&SelfReferencingUser{}, "UserFriends")
 	DB.AutoMigrate(&SelfReferencingUser{})
 
-	friend := SelfReferencingUser{}
+	friend1 := SelfReferencingUser{Name: "friend1_m2m"}
-	if err := DB.Create(&friend).Error; err != nil {
+	if err := DB.Create(&friend1).Error; err != nil {
+		t.Errorf("no error should happen, but got %v", err)
+	}
+
+	friend2 := SelfReferencingUser{Name: "friend2_m2m"}
+	if err := DB.Create(&friend2).Error; err != nil {
 		t.Errorf("no error should happen, but got %v", err)
 	}
 
 	user := SelfReferencingUser{
-		Friends: []*SelfReferencingUser{&friend},
+		Name:    "self_m2m",
+		Friends: []*SelfReferencingUser{&friend1, &friend2},
 	}
+
 	if err := DB.Create(&user).Error; err != nil {
 		t.Errorf("no error should happen, but got %v", err)
 	}
+
+	if DB.Model(&user).Association("Friends").Count() != 2 {
+		t.Errorf("Should find created friends correctly")
+	}
+
+	var newUser = SelfReferencingUser{}
+
+	if err := DB.Preload("Friends").First(&newUser, "id = ?", user.ID).Error; err != nil {
+		t.Errorf("no error should happen, but got %v", err)
+	}
+
+	if len(newUser.Friends) != 2 {
+		t.Errorf("Should preload created frineds for self reference m2m")
+	}
 }

join_table_handler.go

@@ -82,55 +82,40 @@ func (s JoinTableHandler) Table(db *DB) string {
 	return s.TableName
 }
 
-func (s JoinTableHandler) getSearchMap(db *DB, sources ...interface{}) map[string]interface{} {
+func (s JoinTableHandler) updateConditionMap(conditionMap map[string]interface{}, db *DB, joinTableSources []JoinTableSource, sources ...interface{}) {
-	values := map[string]interface{}{}
-
 	for _, source := range sources {
 		scope := db.NewScope(source)
 		modelType := scope.GetModelStruct().ModelType
 
-		if s.Source.ModelType == modelType {
+		for _, joinTableSource := range joinTableSources {
-			for _, foreignKey := range s.Source.ForeignKeys {
+			if joinTableSource.ModelType == modelType {
+				for _, foreignKey := range joinTableSource.ForeignKeys {
 					if field, ok := scope.FieldByName(foreignKey.AssociationDBName); ok {
-					values[foreignKey.DBName] = field.Field.Interface()
+						conditionMap[foreignKey.DBName] = field.Field.Interface()
 					}
 				}
-		} else if s.Destination.ModelType == modelType {
+				break
-			for _, foreignKey := range s.Destination.ForeignKeys {
-				if field, ok := scope.FieldByName(foreignKey.AssociationDBName); ok {
-					values[foreignKey.DBName] = field.Field.Interface()
 			}
 		}
 	}
-	}
-	return values
 }
 
 // Add create relationship in join table for source and destination
 func (s JoinTableHandler) Add(handler JoinTableHandlerInterface, db *DB, source interface{}, destination interface{}) error {
-	scope := db.NewScope("")
+	var (
-	searchMap := map[string]interface{}{}
+		scope        = db.NewScope("")
+		conditionMap = map[string]interface{}{}
+	)
 
-	// getSearchMap() cannot be used here since the source and destination
+	// Update condition map for source
-	// model types may be identical
+	s.updateConditionMap(conditionMap, db, []JoinTableSource{s.Source}, source)
 
-	sourceScope := db.NewScope(source)
+	// Update condition map for destination
-	for _, foreignKey := range s.Source.ForeignKeys {
+	s.updateConditionMap(conditionMap, db, []JoinTableSource{s.Destination}, destination)
-		if field, ok := sourceScope.FieldByName(foreignKey.AssociationDBName); ok {
-			searchMap[foreignKey.DBName] = field.Field.Interface()
-		}
-	}
-
-	destinationScope := db.NewScope(destination)
-	for _, foreignKey := range s.Destination.ForeignKeys {
-		if field, ok := destinationScope.FieldByName(foreignKey.AssociationDBName); ok {
-			searchMap[foreignKey.DBName] = field.Field.Interface()
-		}
-	}
 
 	var assignColumns, binVars, conditions []string
 	var values []interface{}
-	for key, value := range searchMap {
+	for key, value := range conditionMap {
 		assignColumns = append(assignColumns, scope.Quote(key))
 		binVars = append(binVars, `?`)
 		conditions = append(conditions, fmt.Sprintf("%v = ?", scope.Quote(key)))
@@ -161,9 +146,12 @@ func (s JoinTableHandler) Delete(handler JoinTableHandlerInterface, db *DB, sour
 		scope        = db.NewScope(nil)
 		conditions   []string
 		values       []interface{}
+		conditionMap = map[string]interface{}{}
 	)
 
-	for key, value := range s.getSearchMap(db, sources...) {
+	s.updateConditionMap(conditionMap, db, []JoinTableSource{s.Source, s.Destination}, sources...)
+
+	for key, value := range conditionMap {
 		conditions = append(conditions, fmt.Sprintf("%v = ?", scope.Quote(key)))
 		values = append(values, value)
 	}

model_struct.go

@@ -249,11 +249,13 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 							)
 
 							if foreignKey := field.TagSettings["FOREIGNKEY"]; foreignKey != "" {
-								foreignKeys = strings.Split(field.TagSettings["FOREIGNKEY"], ",")
+								foreignKeys = strings.Split(foreignKey, ",")
 							}
 
-							if foreignKey := field.TagSettings["ASSOCIATIONFOREIGNKEY"]; foreignKey != "" {
+							if foreignKey := field.TagSettings["ASSOCIATION_FOREIGNKEY"]; foreignKey != "" {
-								associationForeignKeys = strings.Split(field.TagSettings["ASSOCIATIONFOREIGNKEY"], ",")
+								associationForeignKeys = strings.Split(foreignKey, ",")
+							} else if foreignKey := field.TagSettings["ASSOCIATIONFOREIGNKEY"]; foreignKey != "" {
+								associationForeignKeys = strings.Split(foreignKey, ",")
 							}
 
 							for elemType.Kind() == reflect.Slice || elemType.Kind() == reflect.Ptr {
@@ -264,6 +266,13 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 								if many2many := field.TagSettings["MANY2MANY"]; many2many != "" {
 									relationship.Kind = "many_to_many"
 
+									{ // Foreign Keys for Source
+										joinTableDBNames := []string{}
+
+										if foreignKey := field.TagSettings["JOINTABLE_FOREIGNKEY"]; foreignKey != "" {
+											joinTableDBNames = strings.Split(foreignKey, ",")
+										}
+
 										// if no foreign keys defined with tag
 										if len(foreignKeys) == 0 {
 											for _, field := range modelStruct.PrimaryFields {
@@ -271,15 +280,29 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 											}
 										}
 
-									for _, foreignKey := range foreignKeys {
+										for idx, foreignKey := range foreignKeys {
 											if foreignField := getForeignField(foreignKey, modelStruct.StructFields); foreignField != nil {
 												// source foreign keys (db names)
 												relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.DBName)
-											// join table foreign keys for source
+
-											joinTableDBName := ToDBName(reflectType.Name()) + "_" + foreignField.DBName
+												// setup join table foreign keys for source
-											relationship.ForeignDBNames = append(relationship.ForeignDBNames, joinTableDBName)
+												if len(joinTableDBNames) > idx {
+													// if defined join table's foreign key
+													relationship.ForeignDBNames = append(relationship.ForeignDBNames, joinTableDBNames[idx])
+												} else {
+													defaultJointableForeignKey := ToDBName(reflectType.Name()) + "_" + foreignField.DBName
+													relationship.ForeignDBNames = append(relationship.ForeignDBNames, defaultJointableForeignKey)
 												}
 											}
+										}
+									}
+
+									{ // Foreign Keys for Association (Destination)
+										associationJoinTableDBNames := []string{}
+
+										if foreignKey := field.TagSettings["ASSOCIATION_JOINTABLE_FOREIGNKEY"]; foreignKey != "" {
+											associationJoinTableDBNames = strings.Split(foreignKey, ",")
+										}
 
 										// if no association foreign keys defined with tag
 										if len(associationForeignKeys) == 0 {
@@ -288,28 +311,22 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 											}
 										}
 
-									for _, name := range associationForeignKeys {
+										for idx, name := range associationForeignKeys {
-
-										// In order to allow self-referencing many2many tables, the name
-										// may be followed by "=" to allow renaming the column
-										parts := strings.Split(name, "=")
-										name = parts[0]
-
 											if field, ok := toScope.FieldByName(name); ok {
 												// association foreign keys (db names)
 												relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, field.DBName)
 
-											// If a new name was provided for the field, use it
+												// setup join table foreign keys for association
-											name = field.DBName
+												if len(associationJoinTableDBNames) > idx {
-											if len(parts) > 1 {
+													relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, associationJoinTableDBNames[idx])
-												name = parts[1]
+												} else {
-											}
-
 													// join table foreign keys for association
-											joinTableDBName := ToDBName(elemType.Name()) + "_" + name
+													joinTableDBName := ToDBName(elemType.Name()) + "_" + field.DBName
 													relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, joinTableDBName)
 												}
 											}
+										}
+									}
 
 									joinTableHandler := JoinTableHandler{}
 									joinTableHandler.Setup(relationship, many2many, reflectType, elemType)
@@ -412,11 +429,13 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 							)
 
 							if foreignKey := field.TagSettings["FOREIGNKEY"]; foreignKey != "" {
-								tagForeignKeys = strings.Split(field.TagSettings["FOREIGNKEY"], ",")
+								tagForeignKeys = strings.Split(foreignKey, ",")
 							}
 
-							if foreignKey := field.TagSettings["ASSOCIATIONFOREIGNKEY"]; foreignKey != "" {
+							if foreignKey := field.TagSettings["ASSOCIATION_FOREIGNKEY"]; foreignKey != "" {
-								tagAssociationForeignKeys = strings.Split(field.TagSettings["ASSOCIATIONFOREIGNKEY"], ",")
+								tagAssociationForeignKeys = strings.Split(foreignKey, ",")
+							} else if foreignKey := field.TagSettings["ASSOCIATIONFOREIGNKEY"]; foreignKey != "" {
+								tagAssociationForeignKeys = strings.Split(foreignKey, ",")
 							}
 
 							if polymorphic := field.TagSettings["POLYMORPHIC"]; polymorphic != "" {