1. 了解INSTEAD OF触发器的作用 INSTEAD OF触发器是SQL Server中一种特殊类型的触发器,它可以代替默认的INSERT、UPDATE和DELETE触发器,用于在对表进行插入、更新和删除操作时执行自定义的逻辑。 2. 创建表和视图 在实现INSTEAD OF触发器之前,我们先创建一个表和一个视图。表用于存储数据,视图用于展示数据。 创建表...
INSREAD OF是指定执行 DML 触发器而不是触发 SQL 语句,因此,其优先级高于触发语句的操作。 2 FOR类的语法 CREATE TRIGGERtf_name--自定义触发器的名称 ONtable--此处为表名,触发器的表名,意为在哪个表创建触发 FORINSERT--触发类型:INSERT、UPDATE、DELETE;分别意为插入时、更新时、删除时触发,依据英文意思理...
create trigger delete_student on student instead of delete as --如果要删除student表数据,那么需要级联删除 declare @sno varchar(20); set @sno = sno from deleted --deleted固定格式,为删除执行所能删除的数据,并没有执行删除,而是把他们显示出来,在这获得要删除的数据的sno,然后先删除其他表中此sno的数据...
1altertriggertrigger_学生_Delete2on学生3insteadofDelete4as5begin6select学号, 姓名fromdeleted7end89deletefrom学生where学号=4 上例中定义了“trigger学生_Delete”触发器,该触发器从“delete”表中打印出所要删除的学生.在执行“delete”操作后,会发现“学号 = 4”的学生并未被删除, 原因在于“trigger学生Delete...
SQL Server 2005中触发器可以分为两类:DML触发器和DDL触发器,其中DDL触发器它们会影响多种数据定义语言语句而激发,这些语句有create、alter、drop语句。 DML触发器分为: 1、 after触发器(之后触发) a、 insert触发器 b、 update触发器 c、 delete触发器 after触发器要求只有执行某一操作insert、update、delete之后...
Since cascading DELETEs and UPDATEs weren't provided through declarative RI until the release of SQL Server 2000, the only way to do this nicely was to use triggers, since any referential integrity constraints would restrict the DELETE or UPDATE. Sure, you could also do this in a stored ...
Since cascading DELETEs and UPDATEs weren't provided through declarative RI until the release of SQL Server 2000, the only way to do this nicely was to use triggers, since any referential integrity constraints would restrict the DELETE or UPDATE. Sure, you could also do this in a stored ...
因为Instead of 触发器在约束之前执行，所以它可以对约束进行一些预处理。五：使用T-SQL语句来创建触发器基本语句如下：create trigger trigger_nameon {table_name | view_name}{for | After | Instead of }[ insert, update,delete ]assql_statement六：删除触发器：基本语句如下：drop trigger ...
The FROM clause cannot be specified in a DELETE statement that references, either directly or indirectly, a view with anINSTEAD OFtrigger defined on it. For more information about INSTEAD OF triggers, seeCREATE TRIGGER (Transact-SQL).
l Instead Of触发器:这类触发器一般是用来取代原本的操作,在记录变更之前发生的,它并不去执行原来SQL语句里的操作(Insert、Update、Delete),而去执行触发器本身所定义的操作。 11.3 DML触发器的工作原理 在SQL Server 2005里,为每个DML触发器都定义了两个特殊的表,一个是插入表,一个是删除表。这两个表是建在...