DROP TRIGGER (Transact-SQL)

Artikkeli
12/29/2022

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance

Removes one or more DML or DDL triggers from the current database.

Syntax

-- Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger)  
  
DROP TRIGGER [ IF EXISTS ] [schema_name.]trigger_name [ ,...n ] [ ; ]  
  
-- Trigger on a CREATE, ALTER, DROP, GRANT, DENY, REVOKE or UPDATE statement (DDL Trigger)  
  
DROP TRIGGER [ IF EXISTS ] trigger_name [ ,...n ]   
ON { DATABASE | ALL SERVER }   
[ ; ]  
  
-- Trigger on a LOGON event (Logon Trigger)  
  
DROP TRIGGER [ IF EXISTS ] trigger_name [ ,...n ]   
ON ALL SERVER

Arguments

IF EXISTS
Applies to: SQL Server ( SQL Server 2016 (13.x) through current version, SQL Database).

Conditionally drops the trigger only if it already exists.

schema_name
Is the name of the schema to which a DML trigger belongs. DML triggers are scoped to the schema of the table or view on which they are created. schema_name cannot be specified for DDL or logon triggers.

trigger_name
Is the name of the trigger to remove. To see a list of currently created triggers, use sys.server_assembly_modules or sys.server_triggers.

DATABASE
Indicates the scope of the DDL trigger applies to the current database. DATABASE must be specified if it was also specified when the trigger was created or modified.

ALL SERVER
Applies to: SQL Server 2008 (10.0.x) and later.

Indicates the scope of the DDL trigger applies to the current server. ALL SERVER must be specified if it was also specified when the trigger was created or modified. ALL SERVER also applies to logon triggers.

Note

This option is not available in a contained database.

Remarks

You can remove a DML trigger by dropping it or by dropping the trigger table. When a table is dropped, all associated triggers are also dropped.

When a trigger is dropped, information about the trigger is removed from the sys.objects, sys.triggers and sys.sql_modules catalog views.

Multiple DDL triggers can be dropped per DROP TRIGGER statement only if all triggers were created using identical ON clauses.

To rename a trigger, use DROP TRIGGER and CREATE TRIGGER. To change the definition of a trigger, use ALTER TRIGGER.

For more information about determining dependencies for a specific trigger, see sys.sql_expression_dependencies, sys.dm_sql_referenced_entities (Transact-SQL), and sys.dm_sql_referencing_entities (Transact-SQL).

For more information about viewing the text of the trigger, see sp_helptext (Transact-SQL) and sys.sql_modules (Transact-SQL).

For more information about viewing a list of existing triggers, see sys.triggers (Transact-SQL) and sys.server_triggers (Transact-SQL).

Permissions

To drop a DML trigger requires ALTER permission on the table or view on which the trigger is defined.

To drop a DDL trigger defined with server scope (ON ALL SERVER) or a logon trigger requires CONTROL SERVER permission in the server. To drop a DDL trigger defined with database scope (ON DATABASE) requires ALTER ANY DATABASE DDL TRIGGER permission in the current database.

Examples

A. Dropping a DML trigger

The following example drops the employee_insupd trigger in the AdventureWorks2022 database. (Beginning with SQL Server 2016 (13.x) you can use the DROP TRIGGER IF EXISTS syntax.)

IF OBJECT_ID ('employee_insupd', 'TR') IS NOT NULL  
   DROP TRIGGER employee_insupd;

B. Dropping a DDL trigger

The following example drops DDL trigger safety.

Important

Because DDL triggers are not schema-scoped and, therefore do not appear in the sys.objects catalog view, the OBJECT_ID function cannot be used to query whether they exist in the database. Objects that are not schema-scoped must be queried by using the appropriate catalog view. For DDL triggers, use sys.triggers.

DROP TRIGGER safety  
ON DATABASE;

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