I am considering an option for users that will allow them to write their own account numbers or create their own algorythm for creating custom account numbers for customers, but also want an option that will auto-generate them if the user doesn't care by using the identity property in SQL.
I've always heard that if the PK is supposed to mean anything to users (which an account number would), that using the identity feature is a bad idea, but was never really certain on the reason(s) why?
Any suggestions or thoughts on this?