foreign key help

Started by Dale Sykoraabout 21 years ago2 messagesgeneral
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#1Dale Sykora
dalen@czexan.net

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

#2Qingqing Zhou
zhouqq@cs.toronto.edu
In reply to: Dale Sykora (#1)
Re: foreign key help

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

Show quoted text

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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