How to implement look-up tables?

I don't know if this is a postgres question, a gtk+ UI question, or a C
question. So, if I'm in the wrong mail list, please let me know.

I want to implement lookup tables in my applications. I've always (in
Paradox/DOS) used them primarily in one way:

The lookup table contains limited values permitted in a field and
provides consistent case and spelling on each record/tuple.

For example, a lookup table would have the chart of accounts so the user
could select the appropriate account when entering expenses or writing a
check.

I assume that there is a way to implement this in my postgres
applications, but I've not seen how.

All guidance and pointers gladly received.

TIA,

Rich

Dr. Richard B. Shepard, President
Applied Ecosystem Services, Inc.
2404 SW 22nd Street
Troutdale, OR 97060-1247 U.S.A.
+ 1 503-667-4517 (voice) | + 1 503-667-8863 (fax)
rshepard(at)appl-ecosys(dot)com
Making environmentally-responsible mining happen.