Hi,

SQL Server does this automatically for you. Actually, the return value of NEWID() is a 16-byte value that is automatically casted to a string when you use it in a string function such as REPLACE(). If you create a uniqueidentifier field, it only consumes 16 bytes as in the following sample:

CREATE TABLE Test (ID uniqueidentifier DEFAULT NewID(), cValue varchar(30))
INSERT INTO Test (cValue) VALUES ('one')
INSERT INTO Test (cValue) VALUES ('two')
INSERT INTO Test (cValue) VALUES ('three')
SELECT * FROM Test