SET XACT_ABORT ON
SET XACT_ABORT ON时,在事务中,若出现错误,系统即默认回滚事务,但只对非自定义错误有效
SET XACT_ABORT OFF,默认值,在事务中,回滚一个语句还是整个事务视错误的严重程序而定,用户级错误一般不会回滚整个事务
When SET XACT_ABORT is ON, if a Transact-SQL statement raises a run-time error, the entire transaction is terminated and rolled back.
The setting of SET XACT_ABORT is set at execute or run time and not at parse(从语法上分析;解析) time.