Trigger In Sql Server
Trigger is a special kind of Store procedure Modifications to the table are made using INSERT, UPDATE OR DELETE trigger will run
It is automatically run
Triggers prevent incorrect , unauthorized, or inconsistent changes to data.
FOR [INSERT/UPDATE/DELETE] AS
IF UPDATE( column_name)
{AND/OR} UPDATE( COLUMN_NAME)...]
{ sql_statements }
Triggers prevent incorrect
Syntax in Trigger:
CREATE TRIGGER trigger_name ON table_nameFOR [INSERT/UPDATE/DELETE] AS
IF UPDATE
{AND/OR} UPDATE
Trigger Rules:
- A table can have only three triggers action per table
: UPDATE, INSERT, DELETE. - Only table owners can create and drop triggers for the table
. This permission cannot be transferred. - A trigger cannot be created
on a view or a temporarytable but triggers can reference them. - They can be used to help ensure the relational integrity of
database . On dropping a table all triggers associatedto the triggers are automatically dropped.
INSERT TRIGGER
- When an INSERT trigger statement is executed
, new rows are added to the trigger table and to the inserted table at the same time. - The inserted table allows to compare the INSERTED rows in the table to the rows in the inserted table.
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