Data Warehouse Alter Table add default value constraint

[esobrino]

I have been trying to add a DEFAULT constraint to a COLUMN.  I saw at least one 2023 post stating to check SQL surface area that, as it read says that the ALTER TABLE is not supported, I added a PRIMARY KEY CONSTRAINT using an ALTER TABLE... it just works and therefore the documentation may need some updates.

I have not found any sample or discussion on the use of ALTER TABLE to specify a DEFAULT value.  Since the documentation is not current there may be a way... the samples of ALTER TABLE to add a DEFAULT CONSTRAINT works well in on-prem SQL-SERVER but not in Microsoft Fabric Data Warehouse.

Hope that someone have some news about this...

[AndyDDC · Accepted solution]

Hi @esobrino default constraints are not supported currently as per the documenation here: Primary, foreign, and unique keys - Microsoft Fabric | Microsoft Learn 

• SQL analytics endpoint and Warehouse don't support default constraints at this time.

There's no news when they will be public either.

The ALTER TABLE support in the T-SQL Surface Area documenation states "

• ALTER TABLE ADD/ALTER/DROP COLUMN

And as you've discovered, ALTER TABLE is supported when creating unique, primary key, and foreign key constraints.

T-SQL surface area - Microsoft Fabric | Microsoft Learn

I hope that helps

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