--- In firebird-support@yahoogroups.com, Helen Borrie <helebor@...> wrote:

>
> It's not clear quite what the question is here but I'll take a wild
> guess that you mean, is it better (or worse) to save a byte or two in
> the master table record by creating and maintaining two entire extra
> tables containing no data except the key.
>
> Or did I misunderstand the question?

Space is not an issue, it's more a question on good design. I'd just
like to know which one makes sense from a design perspective.

>
> Could you perhaps describe a bit more clearly why you think you would
> need to add these no-user-data tables?

I suppose just doing things along the same track. I have a
CLASSICAL_PRODUCT table, so I can easily list only classical product
simply by using an inner join. Rather than adding a "type" column to
the PRODUCT table (thereby having 2 methods to select classical
product by) should I just continue along the same track as classical
and have a DVD_PRODUCT and MUSIC_PRODUCT table as well (both only
storing the product ID) so I can also just use an inner join to select
product of that type?

TIA