Make clear works

association.go

@@ -138,7 +138,15 @@ func (association *Association) Replace(values ...interface{}) *Association {
 	return association
 }
 
-func (association *Association) Clear(value interface{}) *Association {
+func (association *Association) Clear() *Association {
+	relationship := association.Field.Relationship
+	scope := association.Scope
+	if relationship.kind == "many_to_many" {
+		whereSql := fmt.Sprintf("%v.%v = ?", relationship.joinTable, scope.Quote(ToSnake(relationship.foreignKey)))
+		scope.db.Model("").Table(relationship.joinTable).Where(whereSql, association.PrimaryKey).Delete("")
+	} else {
+		association.err(errors.New("clear only support many to many"))
+	}
 	return association
 }
 

association_test.go

@@ -190,17 +190,19 @@ func TestManyToMany(t *testing.T) {
 	// Replace
 	var languageB Language
 	db.Where("name = ?", "BB").First(&languageB)
-	db.Debug().Model(&user).Association("Languages").Replace(languageB)
+	db.Model(&user).Association("Languages").Replace(languageB)
 	if db.Model(&user).Association("Languages").Count() != 1 {
-		t.Errorf("Relations should be deleted with Delete")
+		t.Errorf("Relations should be replaced")
 	}
 
 	db.Model(&user).Association("Languages").Replace(&[]Language{{Name: "FF"}, {Name: "JJ"}})
 	if db.Model(&user).Association("Languages").Count() != len([]string{"FF", "JJ"}) {
-		t.Errorf("Relations should be deleted with Delete")
+		t.Errorf("Relations should be replaced")
 	}
 
-	// db.Model(&User{}).Many2Many("Languages").Replace(&[]Language{})
+	// Clear
-	// db.Model(&User{}).Related(&[]Language{}, "Languages")
+	db.Model(&user).Association("Languages").Clear()
-	// SELECT `languages`.* FROM `languages` INNER JOIN `user_languages` ON `languages`.`id` = `user_languages`.`language_id` WHERE `user_languages`.`user_id` = 111
+	if db.Model(&user).Association("Languages").Count() != 0 {
+		t.Errorf("Relations should be cleared")
+	}
 }