Trigger in oracle

最新推荐文章于 2025-11-30 20:29:02 发布

转载最新推荐文章于 2025-11-30 20:29:02 发布 · 336 阅读

文章标签：

#triggers #insert #firing #types #delete #oracle

本文介绍了PL/SQL触发器的基础概念及不同类型的触发器，包括行级触发器、语句级触发器、前触发器、后触发器及代替触发器等。详细解释了触发器如何在更新、插入或删除操作时被隐式触发。

Triggers are constructs in PL/SQL that need to be just created and associated with a table. Once they are created, when the table associated with it gets updated due to an UPDATE, INSERT or a DELETE, the triggers get implicitly fired depending upon the instructions passed to them

The types of triggers are:

Row level triggers
Statement level triggers
BEFORE and AFTER triggers

The different types of triggers are:

Row triggers and statement triggers: specifies how many times the trigger should get executed – Once for every row or once for every triggering statement.
Before and after triggers – Before trigger is fired before and update, insert or triggering statement is executed. After trigger is fired after the triggering statement is executed.
Instead of Trigger- Here, the trigger is fired instead of executing the triggering statement
Key triggers – fired on some key action.
Mouse trigger- fired on some mouse navigation
Navigational trigger – fired as a result of some navigation.

The sequence of firing in a text item are as follows::

a) pre - text
b) when new item
c) key-next
d) when validate
e) post text.