Re: Newbie question

maybe an "order number" does not equal an "order id"?

order id= some information that uniquely indentifies an order. It might be of any type/value (i.e. a surrogate key) order number= represents an natural number N that shows that the order was the Nth order comitted to the system.

This is not a made up number, because it has real meaning (in the UoD), but still could be useful as an order id since it is unique (given that a system cannot commit 2 orders at exactly the same time, which would give us a tie)

Note that this is not a surrogate key, since a surrogate key has no correspondence in the UoD. Also for surrogate keys it is not mandatory to be
- Natural Numbers

• increasing (in steps of 1)
• assigned in order of committance M. Evers