Question

I need to change the type of my primary key column on a table from int to guid. The database already has data that I don’t want to lose, and there are foreign keys to consider. Is there a painless way to do this or do I have to manually do it through a big a** script?:) I would appreciate any suggestions

Answer 1

You’ll have to do it the hard way, using scripts:

0) get in single user mode
1) add the new GUID column to the main table, and populate it.
2) add the new FK column to each child table and populate them with an UPDATE FROM

UPDATE c
    SET FKcolumn=p.NewGuid
    FROM ChildTable             c
        INNER JOIN ParentTable  p ON p.OldIntID=c.OldIntId

3) drop the existing int FKs
4) drop the old int columns
5) add the new FKs on the guid column
6) get out of single user mode

you should be able to get SQL Server Management studio to generate the scripts for adding and dropping the columns and keys. Just make the changes in SSMS and click on the “Generate Change Script” toolbar icon and you can cut and paste the code to a text file.