--- In firebird-support@yahoogroups.com, "women_lover_best"
<talbronstien@g...> wrote:

> Hi,
> I have a table with 2 foriegn keys..and We want to make them as
> composite primary key..(f1 + f2)..is it possible in FB?if yes,is it a
> good practice? Performance wise?
> thanks

Hi Women Lover Best (if you say so),

Hmmm, with a yahoo name like that you may want to sign your name at
the end of your post. Unfortunately someone hijacked your thread, but
I saw your question.

Can you do it, you sure can, as long as the fields are declared as not
null, there is no technical problem in doing it.

I would recommend against it though. We have one remaining table that
has a composite primary key. The downside is that we need to use
pretty verbose triggers to define the foreign key relationships to
other tables. It is a throw back to our paradox db history and it will
probably be there for a while yet because it would require me to spend
time I don't have for little commercial gain, but given the choice to
design that table again it would get an ID field in a blink.

So what I would recommend you do is add an ID column to the table. It
is normal for a table to have multiple candidate keys, but just
because a particular set of fields is a candidate key does not mean it
is a sensible way to do it. I would also discourage using a candidate
key defined by a customer as a PK, instead I prefer to generate a
unique number that has no real world meaning to the customer. This
means you do not have to cascade updates etc, because they never care
about changing its value.

Adam