Question

Is there a quick script I can use in SQL Server to change the ID from int to unique identifier without physically going through and doing it manually. I have contemplated code gen to achieve this, but I would have thought using TSQL would be the quickest if possible that is!

Answer 1

You could do it with a script.

ALTER TABLE x ADD COLUMN y uniqueIdentifier null
GO
UPDATE TABLE x SET y = NEWID() --Or NEWSEQUENTIALID() if its safe
GO
ALTER TABLE x ALTER COLUMN y uniqueIdentifier NOT NULL
GO
ALTER TABLE x DROP CONSTRAINT PK_PrimaryKeyConstraintName
GO
ALTER TABLE x DROP COLUMN PrimaryKeyColumn
GO
ALTER TABLE x ADD CONSTRAINT PK_NewPrimaryKeyConstraint PRIMARY KEY CLUSTERED 
( 
    y ASC 
)
GO

Note that this wont deal with your foreign key constraints and will break, if you have foreign key constraints this gets interesting, but I’m sure you can see the pattern.