在这个代码示例中,触发器名称为trg_after_insert,它会在employees表执行插入操作后自动运行。触发器内部可以编写任意 SQL 逻辑,比如在audit_log表中记录员工的插入信息,包括员工ID、操作类型和时间戳。 接下来,我们将重点分析上面代码中的函数与关键字。首先,CREATE TRIGGER语句是用来定义触发器的,紧接着是触发器的执...
Learn everything you need to know about triggers in SQL Server, from creating and using them to troubleshooting errors. Read on to know its pros and cons.
Types of Triggers Two types of triggers are available for SQL Server: INSTEAD OF trigger: The INSTEAD OF trigger allows you to bypass INSERT, UPDATE, or DELETE Data Manipulation Language (DML) statements and execute other statements instead. An INSTEAD OF trigger always overrides the triggering ...
Trigger functions can be applied to both tables and views. It must be noted that there are two basic types of triggers: Instead Of After Nonetheless, of these two forms of triggers, only theInstead Oftrigger can be applied to views, upon the execution of anUpdateaction. On tables, both ...
Types of SQL Triggers In SQL Server, we have 3 groups of triggers: DML (data manipulation language) triggers – We’ve already mentioned them, and they react to DML commands. These are – INSERT, UPDATE, and DELETE DDL (data definition language) triggers – As expected, triggers of th...
一:触发器简介 pl/sql--触发器 Triggers Oracle 可以在DML语句进行触发,可以在DML操作前或操作后进行触发,并且可以对各个行或者语句操作上进行触发. 1.替代触发器 由于在Oracle里,不能直接对由两个以上的表建立的视图进行操作,所以给出了替代触发器。 2.系统触发器 他
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...
In this article, we will review triggers in SQL Server, different types of trigger events, trigger order and NOT FOR REPLICATION in triggers. A trigger is a database object that runs automatically when an event occurs. There are three different types of events. ...
There are three action query types that you use in SQL which are INSERT, UPDATE and DELETE. So, there are three types of triggers and hybrids that come from mixing and matching the events and timings that fire them. Basically, triggers are classified into two main types: After Triggers ...
SHOW TRIGGERS [{FROM | IN} database_name] [LIKE 'pattern' | WHERE expr] FROM 子句用于指定数据库,如果未指定则为默认数据库。SHOW TRIGGERS 语句仅返回具有 TRIGGER 权限的数据库和表的结果。 LIKE 子句(如果存在)指定要匹配的表名称(不是触发器名称),并显示这些表的触发器。可以使用 WHERE 子句指定...