A. Trigger:
Sql server trigger is a special store procedures that are executed automatically in response to the database object, database and server events.
Types of trigger:
- DML Triggers:
This triggers invoked automatically in response to the Insert Update and Delete events automatically.
- DDL Triggers
This triggers fire in response to create alter and drop statements.
Syntax:
CREATE TRIGGER [schema_name.]trigger_name
ON table_name
AFTER {[INSERT],[UPDATE],[DELETE]}
[NOT FOR REPLICATION]
AS
{sql_statements}
In this syntax:
- The schema_name is the name of the schema to which the new trigger belongs. The schema name is optional.
- The trigger_name is the user-defined name for the new trigger.
- The table_name is the table to which the trigger applies.
- The event is listed in the AFTER clause. The event could be INSERT, UPDATE, or DELETE. A single trigger can fire in response to one or more actions against the table.
- The NOT FOR REPLICATION option instructs SQL Server not to fire the trigger when data modification is made as part of a replication process.
- The sql_statements is one or more Transact-SQL used to carry out actions once an event occurs.
