Re: Erwin? Oracle? or me?

Barnel wrote:
>
> Yes it did help Thank you very much.
>
> My next question is why would there be a need to make the distinction between
> identifying and non-identifying relationships?

Well to get the effect you have seen.

You have non-identifying relationships. The objects are just plainly related but it's not a part-of relation. You might want to make it one for province - city and city - neighbourhood, though.

The first example of an identifying relationship that comes to my mind is invoice and invoice line:
Invoicenr is the primary key of invoice. The lines are numbered per invoice. Therefore you can use the primary key of invoice and the line nr to identify an invoice line. This makes the relationship between invoice and invoice line an identifying one.

hth,
Heinz Received on Thu Dec 14 2000 - 07:55:42 CET