defer conn.Close()
	tx.Statement.ConnPool = conn
	return fc(tx)
}

// Transaction start a transaction as a block, return error will rollback, otherwise to commit. Transaction executes an
// arbitrary number of commands in fc within a transaction. On success the changes are committed; if an error occurs
// they are rolled back.
func (db *DB) Transaction(fc func(tx *DB) error, opts ...*sql.TxOptions) (err error) {
	panicked := true

		tx3 := DB.Session(&gorm.Session{PrepareStmt: true})
		if err := tx3.Transaction(func(tx4 *gorm.DB) error {
			// nested transaction
			return tx4.Transaction(func(tx5 *gorm.DB) error {
				return tx5.First(&User{}, "name = ?", "transaction-2").Error
			})
		}); err != nil {
			t.Fatalf("prepare statement and nested transcation coexist" + err.Error())
		}
	})
}

func TestCancelTransaction(t *testing.T) {
	ctx := context.Background()

	DB.Migrator().DropTable(&Token{}, &TokenOwner{})
	DB.AutoMigrate(&Token{}, &TokenOwner{})

	saveTokenOwner := func(owner *TokenOwner) (*TokenOwner, error) {
		var newOwner TokenOwner
		if err := DB.Transaction(func(tx *gorm.DB) error {
			if err := tx.Session(&gorm.Session{FullSaveAssociations: true}).Save(owner).Error; err != nil {
				return err
			}

)

// for Config.cacheStore store PreparedStmtDB key
const preparedStmtDBKey = "preparedStmt"

// Config GORM config
type Config struct {
	// GORM perform single create, update, delete operations in transactions by default to ensure database data integrity
	// You can disable it by setting `SkipDefaultTransaction` to true
	SkipDefaultTransaction bool
	// NamingStrategy tables, columns naming strategy
	NamingStrategy schema.Namer