SQL SERVER – Disable All the Foreign Key Constraint in Database – Enable All the Foreign Key Constraint in Database

Here is an email I received during the weekend.

“Hi Pinal,

I am a senior tester in the leading organization and we have two different environments 1) Testing 2) Production.

As a part of the testing we want to insert garbage data into the database system and see how the application behaves in this scenario. However, there is a small problem. Everytime when I try to insert garbage data in the database system the tables start giving me error that due to constraints on the table, I need to populate data in certain order and it has to be correct. Actually, we want to populate the bad data and see how application reacts to it. Upon talking to development team regarding this they suggested that we should skip this test as due to contraints there will be never bad data. Though, I understand their viewpoint, I must document how the application behaves when there are bad data and data integrity is compromised.

Is there any way I can disable all the Constraint temporarily and load the random data, test my system and later delete all the inserted data and enable the Constraint back?”

This is indeed a great question, I often come across this question again and again. Here is a quick script I have written in my early career which I still use it when I need to do something similar.

-- Disable all the constraint in database
EXEC sp_msforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"


-- Enable all the constraint in database
EXEC sp_msforeachtable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"

Remember above script when executed right away enable or disable constraints so be extremely careful to execute on production server.

There is one more thing, when you have disabled the constraint, you can delete the data from the table but if you attempt to truncate the table, it will still give you an error. If you need to truncate the table you will have to actually drop all the constraints. Do you use similar script in your environment? If yes, please leave a comment along with the script and I will post it on blog with due credit.

Reference: Pinal Dave (http://blog.sqlauthority.com)