[Zope] constraint in postgres

[Andrew Kenneth Milton]

+-------[ Fred Yankowski ]----------------------
| Isn't this a classic "referential integrity" case?  If so, you could
| try this:
| 
| 	create table country (id serial primary key, ...);
| 
| 	create table address (id serial,
| 			      country_id int4 references country, ...);

references country(id) more than likely, unless you have a unique country_id in country.
That is you don't need two fields with basicaly the same info, when you already have
a unique serial id which is the primary key.

This also stops you from inserting into address without a valid country, as
a bonus side effect.

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