How can foreign key constraints be temporarily disabled using T-SQL?

Question

Are disabling and enabling foreign key constraints supported in SQL Server? Or is my only option to drop and then re-create

Answer 1

To disable the constraint you have ALTER the table using NOCHECK

ALTER TABLE [TABLE_NAME] NOCHECK CONSTRAINT [ALL|CONSTRAINT_NAME]

To enable you to have to use double CHECK:

ALTER TABLE [TABLE_NAME] WITH CHECK CHECK CONSTRAINT [ALL|CONSTRAINT_NAME]

• Pay attention to the double CHECK CHECK when enabling.
• ALL means for all constraints in the table.

Once completed, if you need to check the status, use this script to list the constraint status. Will be very helpfull:

    SELECT (CASE 
        WHEN OBJECTPROPERTY(CONSTID, 'CNSTISDISABLED') = 0 THEN 'ENABLED'
        ELSE 'DISABLED'
        END) AS STATUS,
        OBJECT_NAME(CONSTID) AS CONSTRAINT_NAME,
        OBJECT_NAME(FKEYID) AS TABLE_NAME,
        COL_NAME(FKEYID, FKEY) AS COLUMN_NAME,
        OBJECT_NAME(RKEYID) AS REFERENCED_TABLE_NAME,
        COL_NAME(RKEYID, RKEY) AS REFERENCED_COLUMN_NAME
   FROM SYSFOREIGNKEYS
ORDER BY TABLE_NAME, CONSTRAINT_NAME,REFERENCED_TABLE_NAME, KEYNO