Primary Key on existing data

Question

I need to delete existing PK from table and create new in new column. Because column for new PK was added later (after table creation) - we have nulls for old rows. Should I use UPDATE statement or there is some option in "ADD CONSTRAINT" clause which automatically determine NULLs and generate GUIDs for them?

Thanks for help.

score 1 · Accepted Answer · answered Mar 06 '13 at 11:32

This is what you have to do.

UPDATE TABLE1
SET GUID = NEWID()
WHERE GUID IS NULL

Now to add a new contstraint, you will have tod elete the old one. This is how you can do it:

ALTER TABLE TABLE1
DROP CONSTRAINT PrimaryKeyName

ALTER TABLE TABLE1
ADD CONSTRAINT PrimaryKeyName PRIMARY KEY (GUID)

Primary Key on existing data

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