posted on Tuesday, December 13, 2005 12:08 AM by bknight

Preventing Schema Changes with DDL Triggers

DDL triggers are a fantastic way to prvent DDL events in a production database. In the following database triggers, you prevent any type of DDL event, like altering a sproc in production. If a statement is issued, the statement is logged, rolled back and a user receives a message. Databae triggers can be raised at nearly any level. The below example captures any database-level event. There are also server DDL triggers that captures server events like creating logins or changing the configuration of a database.

SET ANSI_NULLS ON
SET
QUOTED_IDENTIFIER
ON
GO

CREATE TRIGGER PreventDDL
ON DATABASE

FOR
DDL_DATABASE_LEVEL_EVENTS
AS

PRINT 'DDL events are prohibited, your statement was rolled back.'
DECLARE @data XML
;
DECLARE @schema sysname
;
DECLARE @object sysname
;
DECLARE @eventType sysname;

SET @data = EVENTDATA()
SET @eventType = @data.value('(/EVENT_INSTANCE/EventType)[1]', 'sysname'
);
SET @schema = @data.value('(/EVENT_INSTANCE/SchemaName)[1]', 'sysname'
);
SET @object = @data.value('(/EVENT_INSTANCE/ObjectName)[1]', 'sysname')

INSERT [dbo].[DatabaseLog]
([PostTime],

[DatabaseUser]
,

[Event]
,

[Schema]
,

[Object]
,

[TSQL]
,

[XmlEvent]
)

VALUES
(GETDATE(), CONVERT(sysname, CURRENT_USER), @eventType,

CONVERT(sysname, @schema), CONVERT(sysname, @object),

@data
.value('(/EVENT_INSTANCE/TSQLCommand)[1]', 'nvarchar(max)'),

@data
)

ROLLBACK

-- Brian Knight

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