You may want to have a look at pg DOMAIN (also conforms to SQL standard).
http://www.postgresql.org/docs/8.0/static/sql-createdomain.html
Regards,
Qingqing
"Dale Sykora" <dalen@czexan.net> writes
> I am building a database that has about 20 fields in various tables that
> I would like to constrain to a small group (<=5) of choices. Rather
> that refer to 20 seperate tables, I would like to refer to 1 table that
> contained category and choice fields.
>
> for example
>
> choices table
>
> category | choice
> -----------------
> color | red
> color | green
> size | small
> size | big
> shape | circle
> shape | square
>
> item table
>
> item | shape
> -----------------
> box | constrain to choices(choice) where category='shape'
>
>
>
> Is there an easy way to do this, or is it better to have many
> choices_category tables?
>
> Thanks,
>
> Dale
>
>
>
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