ID  uint   `gorm:"primarykey"`
		UID uint32 `gorm:"not null;autoIncrement"`
	}

	type Event2 struct {
		ID  uint   `gorm:"primarykey"`
		UID uint16 `gorm:"not null;autoIncrement"`
	}

	var err error
	err = DB.Migrator().DropTable(&Event{})
	if err != nil {
		t.Errorf("DropTable err:%v", err)
	}

	// create sequence
	err = DB.Table("events").AutoMigrate(&Event1{})
	if err != nil {

	}

	t.Run("First", func(t *testing.T) {
		var first User
		if err := DB.Where("name = ?", "find").First(&first).Error; err != nil {
			t.Errorf("errors happened when query first: %v", err)
		} else {
			CheckUser(t, first, users[0])
		}
	})

	t.Run("Last", func(t *testing.T) {
		var last User
		if err := DB.Where("name = ?", "find").Last(&last).Error; err != nil {