1.定义一个事务的开始 : begin transaction;
begin {tran|transation} [ tran_name|@tran_name_variable ] --给事务分配名称, [ with mark[ 'description' ] ]
2.提交一个事务 : commit transaction;
3.回滚事务 : rollback transaction
4.在事务中设置保存点: save transaction