If you wanted to get a column to act like an identity column but to be a uniqueidentifier instead of an int you could do this:

CREATE TABLE dbo.yourtable

(

pk_col AS newid(),

xxx varchar(10) not null

);

GO

INSERT dbo.yourtable (xxx) VALUES ('www'),('rrr');

SELECT *

FROM dbo.yourtable;

The problem here is that you can't use the column as a Primary key or a Unique key or as part of a clustered index. 🙁