Hi,

Any takers on this? An explanation would be very helpful!

thanks,

David

---------------------- Forwarded by David Hay/Lex/Lexmark on 28/10/2003
03:09 PM ---------------------------


David Hay
23/10/2003 05:28 PM

To: firebird-support@yahoogroups.com
cc:

Subject: When to mark as foreign key or not? (Document link: David Hay)

Hi,

I have a forms table, a categories table, and a formcategory table which
links the form with the categories it is in.

I automatically set the form_id and category_id in the formcategory table
(that's all it contains) as foreign keys to forms.id and categories.id
respectively. However this automatically creates an index on category_id,
but with a selectivity of 100.

So...will this be problematic in terms of the optimizer? Should I handle
the foreign key stuff myself? It seems like the right thing to
do...but???!

Any advice appreciated,

Cheers,

David