Help changing all PK and FK datatypes from uniqueidentifier to nvarchar(128)

Question

Is there a simple script to iterate through all my tables and change my PK and FK datatypes to nvarchar(128)? I don't want to have to go through each table manually, remove relationships, and change each key one by one. Here is my db schema if it helps.

Answer 1

Hi Man_Cat,
According to your description, you are looking for the script to update all the PK and FK datatypes from uniqueidentifier to nvarchar(128), right?
Based on my research, we cannot change the data type of the Primary Key and Foreign Key directly as Tom said. However, we can drop the PK and FK and recreate them use the query below.
--This will drop the primary key temporarily
ALTER TABLE MyTable
drop CONSTRAINT PK_MyTable
--change data type
ALTER TABLE MyTable
ALTER COLUMN PrimaryKeyID BigInt
--add primary key
ALTER TABLE MyTable
ADD CONSTRAINT PK_MyTable PRIMARY KEY (PrimaryKeyID)
Reference
http://forums.asp.net/t/1528279.aspx?Alter+script+to+change+the+Primarykey+Column+datatype
Regards,
Charlie Liao
TechNet Community Support