if option.CheckOption != "" {
		sql.WriteString(" ")
		sql.WriteString(option.CheckOption)
	}
	return m.DB.Exec(m.Explain(sql.String(), m.DB.Statement.Vars...)).Error
}

// DropView drop view
func (m Migrator) DropView(name string) error {
	return m.DB.Exec("DROP VIEW IF EXISTS ?", clause.Table{Name: name}).Error
}

// GuessConstraintAndTable guess statement's constraint and it's table based on name

		// restore prepared statement
		if isPreparedStmtTx {
			db.Statement.ConnPool = preparedStmtTx
		}
	} else {
		db.AddError(ErrUnsupportedDriver)
	}
	return db
}

// Exec executes raw sql
func (db *DB) Exec(sql string, values ...interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.SQL = strings.Builder{}

	if strings.Contains(sql, "@") {

	// 1. g1 begin tx, g1 is requeue because of waiting for the system call, now `db.ConnPool` db.numOpen == 1.
	// 2. g2 select lock `conn.PrepareContext(ctx, query)`, now db.numOpen == db.maxOpen , wait for release.
	// 3. g1 tx exec insert, wait for unlock `conn.PrepareContext(ctx, query)` to finish tx and release.
	stmt, err := conn.PrepareContext(ctx, query)
	if err != nil {
		cacheStmt.prepareErr = err
		db.Mux.Lock()
		delete(db.Stmts, query)

	}

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

	DB.Exec(`CREATE EXTENSION IF NOT EXISTS "uuid-ossp";`)

	err = DB.AutoMigrate(&MissPKUser{}, &MissPKLanguage{})
	if err != nil {
		t.Fatalf("AutoMigrate err:%v", err)
	}

	// patch

		t.Errorf("Raw with Rows should find one record with name 3")
	}

	DB.Exec("update users set name=? where name in (?)", "jinzhu-raw", []string{user1.Name, user2.Name, user3.Name})
	if DB.Where("name in (?)", []string{user1.Name, user2.Name, user3.Name}).First(&User{}).Error != gorm.ErrRecordNotFound {
		t.Error("Raw sql to update records")
	}

	DB.Exec("update users set age=? where name = ?", gorm.Expr("age * ? + ?", 2, 10), "jinzhu-raw")

			dbDSN = tidbDSN
		}
		db, err = gorm.Open(mysql.Open(dbDSN), cfg)
	default:
		log.Println("testing sqlite3...")
		db, err = gorm.Open(sqlite.Open(filepath.Join(os.TempDir(), "gorm.db")), cfg)
		if err == nil {
			db.Exec("PRAGMA foreign_keys = ON")
		}
	}

	if err != nil {
		return
	}

	if debug := os.Getenv("DEBUG"); debug == "true" {
		db.Logger = db.Logger.LogMode(logger.Info)
	} else if debug == "false" {