A DDL trigger is defined to handle a DDL statement event, like create, alter and drop tables, views, indexes, etc. DDL triggers can be used to generate warning messages on database object changes. The format of creating a DDL trigger should be:

CREATE TRIGGER trigger_name ON DATABASE

AFTER ddl_event_types

AS

statements

GO

-- ddl_event_types are keywords like:

-- CREATE_TABLE, ALTER_TABLE, DROP_TABLE, ...

Below is a simple example of creating a DDL trigger to generate messages on ALTER_TABLE events:

USE GlobalGuideLineDatabase;

GO

CREATE TRIGGER ddl_message ON DATABASE

AFTER ALTER_TABLE

AS

PRINT 'Someone is changing tables!';

GO

ALTER TABLE ggl_users

ALTER COLUMN id INT NOT NULL;

GO

Someone is changing tables!