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SQL Server FAQ - What Are Triggers
(Continued from previous topic...)
What Are Triggers?
A trigger is a special kind of stored procedure that automatically executes when an event occurs
in the database server. A trigger is really an event handler.
SQL Server allows users to create triggers (event handlers) for 3 types of events:
- DML Event - Occurs when a DML (Data Manipulation Language) statement: INSERT, UPDATE or DELETE,
- DDL Event - Occurs when a DDL (Data Definition Language) statement: CREATE, ALTER, or DROP,
- Logon Event - Occurs when a user logins to the Server.
There are 3 different types of triggers (event handlers) based on the types of events they are triggered by:
- DML Trigger - Executes in response to a DML event.
- DDL Trigger - Executes in response to a DDL event.
- Logon Trigger - Executes in response to a logon event.
(Continued on next topic...)
- What Are Triggers?
- What Are the Basic Features of a Trigger?
- How To Create a Simple Table to Test Triggers?
- How To Create a DML Trigger using CREATE TRIGGER Statements?
- How To Test a DML Trigger?
- How To List All Triggers in the Database with sys.triggers?
- How To Modify Existing Triggers using "ALTER TRIGGER"?
- How To Delete Existing Triggers using "DROP TRIGGER"?
- How To Get the Definition of a Trigger Back?
- How To Disable Triggers using "DISABLE TRIGGER"?
- How To Create a Trigger for INSERT Only?
- How To See the Event List of an Existing Trigger using sys.trigger_events?
- How To Access the Inserted Record of an Event?
- How To Access the Deleted Record of an Event?
- How To Improve the Trigger to Handle NULL Values?
- What Happens to a Trigger with Multiple Affected Rows?
- How To Override DML Statements with Triggers?
- How To Create a DDL Trigger using "CREATE TRIGGER" Statements?
- Can You Roll Back the DDL Statement in a Trigger?
- Can You Create a Logon Trigger in SQL Server 2005 Express Edition?