For DELETE operations, the return value should be OLD.The return value of a row-level trigger fired AFTER or a statement-level trigger fired BEFORE or AFTERis always ignored; it might as well be null. However, any of these types of triggers might still abort the entire operation by raisin...
无涯教程-PL/SQL - 触发器(Triggers) 在本章中,无涯教程将讨论PL/SQL中的触发器,触发器是存储的程序,在发生某些事件时会自动执行或触发。 创建触发器 创建触发器的语法是- CREATE [OR REPLACE ] TRIGGER trigger_name {BEFORE | AFTER | INSTEAD OF } {INSERT [OR] | UPDATE [OR] | DELETE} [OF co...
--查找触发器的名称selectobject_namefromuser_objectswhereonject_type='TRIGGER';--得到名称后, 查找触发器的内容select*fromuser_sourcewherename='first_trg'orderbyline; (二)触发器的语法 1.DDL事件的触发器: create alter drop CREATE[OR REPLACE]TRIGGER--触发器的名称[BEFORE | AFTER | INTEAD OF][DDL...
In this example, we have created a trigger which will insert rows into an audit table before each updating of transaction table. Whenever user UPDATE data ofbank_transactions, the old data will be inserted intobank_transactions_auditby trigger for audit or backup purpose. 3.1 Create a bank tra...
In this example, we have created aINSTEAD OFtrigger which will insert rows into respective tables of aviewwhen we execute the insert statement on a view. 1.1 Create tables. customer_details CREATE TABLEcustomer_details ( customer_id number(10)primary key, ...
PL/SQL - Triggers - In this chapter, we will discuss Triggers in PL/SQL. Triggers are stored programs, which are automatically executed or fired when some events occur. Triggers are, in fact, written to be executed in response to any of the following eve
pl/sql block; (1)before语句触发器 //禁止工作人员在周一改变雇员信息 createorreplacetriggertr_change_emp beforeinsertorupdateordelete---insert update delete三种操作触发触发器onempbeginifto_char(sysdate,'DY','nls_date_language=AMERICAN')IN('MON')then---自定义错误输出raise_application_error(-20001...
SQL 型 V4.3.0 参考指南 配置项和系统变量 配置项 租户级别配置项 plsql_optimize_level 更新时间:2024-11-20 16:06:47 plsql_optimize_level 用于指定编译优化级别。 属性描述 参数类型整数类型 默认值1 取值范围0:表示不开启优化 1:表示开启优化
NEW 和 OLD 是特殊变量,您可以将其与 PL/SQL 触发器配合使用,而不必显式地定义这些变量。 NEW 是一个伪记录名,它引用行级触发器中的插入和更新操作的新表行。它的用法是:NEW.column,其中column是表中对其定义此触发器的列的名称。 在行级前触发器中使用时,:NEW.column的初始内容是所要插入的新行中的列...
如果删除操作已激活触发器,那么为 True。否则,为 False。 INSERTING 如果插入操作已激活触发器,那么为 True。否则,为 False。 UPDATING 如果更新操作已激活触发器,那么为 True。否则,为 False。 在WHEN 子句或 PL/SQL 语句中,可将这些谓词指定为单个搜索条件,也可将它们指定为复合搜索条件内的布尔因子。