SQL Server FAQ - Creating Triggers for INSERT Statements Only

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By: FYIcenter.com

How To Create a Trigger for INSERT Only?

The trigger, dml_message, provided in previous tutorials was defined to handle all 3 types of DML statements, INSERT, UPDATE, and DELETE.

If you do not want the trigger to handle all 3 types of DML statements, you can list only 1 or 2 of the statement keywords. For example, the following SQL script defines a trigger that only handle the INSERT statement events:

USE FyiCenterData
GO

CREATE TRIGGER new_user ON fyi_users
AFTER INSERT 
AS
  PRINT 'Time: '+CONVERT(VARCHAR(12),GETDATE())
    + ' New users added.';
GO

INSERT INTO fyi_users (name) VALUES ('Marc Kumar');
GO
Time: Jul  1 2007 
Records are inserted, updated, or deleted in fyi_users
Time: Jul  1 2007  New users added.
(1 row(s) affected)

UPDATE fyi_users SET email='marc@fyicenter' 
   WHERE name = 'Marc Kumar';
GO
Time: Jul  1 2007 
Records are inserted, updated, or deleted in fyi_users
(1 row(s) affected)

Notice that the INSERT statement triggered two triggers to be executed: dml_message and new_user. But the UPDATE statement triggered one trigger to be executed: dml_message as expected.

It is also interesting to know that when multiple triggers are defined to handle the same event, the oldest (defined first) will be executed first.

(Continued on next topic...)