Oracle triggers (reprinted and collected)

There are two types of triggers: after and before. The difference is that each commit transaction is triggered once and each row of data is updated once. Pay attention to this when using the trigger to avoid failure to achieve the goal.

The syntax for Oracle to generate database triggers is:

Create [or replace] trigger name trigger time trigger event

On Table Name

[For each row]

PL/SQL statements

Where:

Trigger name: name of the trigger object. Because the trigger is automatically executed by the database

So the name is only a name and has no substantive purpose.

Trigger time: specifies when the trigger is executed. This value is optional:

Before --- indicates that the trigger is executed before the database action;

After --- indicates that the logpilot executes the database action.

Trigger event: Specifies which database actions will trigger this trigger:

Insert: This trigger is triggered when the database is inserted;

Update: This trigger is triggered when the database is modified;

Delete: This trigger is triggered when a database is deleted.

Table Name: The table where the database trigger is located.

For each row: the trigger for each row of the table is executed once. If you do not have this

To the entire table.

For example, the following trigger is triggered before the table auths is updated to prevent

Weekend table modification:

Create trigger auth_secure

Before insert or update or delete // triggered before update of the whole table

On auths

Begin

If (to_char (sysdate, 'dy ') = 'sun'

Raise_application_error (-20600, 'table auths' cannot be modified on weekends ');

End if;

End

Reprinted: http://lorry1113.javaeye.com/blog/513849