DB.Model(&blog).Association("Tags").Find(&tags)
	if !compareTags(tags, []string{"tag1", "tag2", "tag3"}) {
		t.Fatalf("Should find 3 tags")
	}

	var blog1 Blog
	DB.Preload("Tags").Find(&blog1)
	if !compareTags(blog1.Tags, []string{"tag1", "tag2", "tag3"}) {
		t.Fatalf("Preload many2many relations")
	}

	// Replace
	tag5 := &Tag{Locale: "ZH", Value: "tag5"}
	tag6 := &Tag{Locale: "ZH", Value: "tag6"}

		t.Fatalf("errors happened when update: %v", err)
	}

	var user2 User
	DB.Preload("Account").Find(&user2, "id = ?", user.ID)
	CheckUser(t, user2, user)

	user.Account.Number += "new"
	if err := DB.Save(&user).Error; err != nil {
		t.Fatalf("errors happened when update: %v", err)
	}

	var user3 User
	DB.Preload("Account").Find(&user3, "id = ?", user.ID)

	CheckUser(t, user2, user3)

func TestAssociationError(t *testing.T) {
	user := *GetUser("TestAssociationError", Config{Pets: 2, Company: true, Account: true, Languages: 2})
	DB.Create(&user)

	var user1 User
	DB.Preload("Company").Preload("Pets").Preload("Account").Preload("Languages").First(&user1)

	var emptyUser User
	var err error
	// belongs to
	err = DB.Model(&emptyUser).Association("Company").Delete(&user1.Company)

		}

		tx := preloadDB(db, db.Statement.ReflectValue, db.Statement.Dest)
		if tx.Error != nil {
			return
		}

		db.AddError(preloadEntryPoint(tx, joins, &tx.Statement.Schema.Relationships, db.Statement.Preloads, db.Statement.Preloads[clause.Associations]))
	}
}

func AfterQuery(db *gorm.DB) {
	// clear the joins after query because preload need it

		Preload("Toys", func(db *gorm.DB) *gorm.DB {
			return db.Table("toys").Select("name")
		}).Count(&count12).Error; err == nil {
		t.Errorf("error should raise when using preload without schema")
	}

	var count13 int64
	if err := DB.Model(User{}).
		Where("name in ?", []string{user1.Name, user2.Name, user3.Name}).
		Preload("Toys", func(db *gorm.DB) *gorm.DB {

		db = scope(db)
	}
	return db
}

// Preload preload associations with given conditions
//
//	// get all users, and preload all non-cancelled orders
//	db.Preload("Orders", "state NOT IN (?)", "cancelled").Find(&users)
func (db *DB) Preload(query string, args ...interface{}) (tx *DB) {
	tx = db.getInstance()
	if tx.Statement.Preloads == nil {
		tx.Statement.Preloads = map[string][]interface{}{}
	}

	// ErrInvalidValueOfLength invalid values do not match length
	ErrInvalidValueOfLength = errors.New("invalid association values, length doesn't match")
	// ErrPreloadNotAllowed preload is not allowed when count is used
	ErrPreloadNotAllowed = errors.New("preload is not allowed when count is used")
	// ErrDuplicatedKey occurs when there is a unique key constraint violation
	ErrDuplicatedKey = errors.New("duplicated key not allowed")

	AssertEqual(t, nil, err)

	var findUser1 User
	err = DB.Preload("Languages").Where("id = ?", user1.ID).First(&findUser1).Error
	AssertEqual(t, nil, err)
	AssertEqual(t, user1, findUser1)

	var findUser2 User
	err = DB.Preload("Languages").Where("id = ?", user2.ID).First(&findUser2).Error
	AssertEqual(t, nil, err)
	AssertEqual(t, user2, findUser2)
}

## Overview

* Full-Featured ORM
* Associations (Has One, Has Many, Belongs To, Many To Many, Polymorphism, Single-table inheritance)
* Hooks (Before/After Create/Save/Update/Delete/Find)
* Eager loading with `Preload`, `Joins`
* Transactions, Nested Transactions, Save Point, RollbackTo to Saved Point
* Context, Prepared Statement Mode, DryRun Mode
* Batch Insert, FindInBatches, Find To Map

	createCallback.Clauses = config.CreateClauses

	queryCallback := db.Callback().Query()
	queryCallback.Register("gorm:query", Query)
	queryCallback.Register("gorm:preload", Preload)
	queryCallback.Register("gorm:after_query", AfterQuery)
	queryCallback.Clauses = config.QueryClauses

	deleteCallback := db.Callback().Delete()