>Cetin, I do not use GUID in PK just because of performance. I don't think they are a waste of space.
>
>I call waste of space when, for example:
>- The tables are not well normalized
>- The programmer tries to store everything under the sun, be it usefull or not
>- Field lenghts are not well studied. For example: the lot number for production lots. It is usually no more than 10 characters, but some suppliers go up to 15. It is hard to find longer lengths. So give it 15, instead of 25-30 just because space is cheap ....

We once had a customer who asked for a c(24) field to store supplier's invoice number. Why? Well, they had one (but large) supplier who had their information system designed with sort-of-meaningful keys. Or someone made their masters degree on that project or something... to the point we almost sensed which professor from which college was behind it.

Of course, the data entry clerks absolutely hated typing those numbers.