From: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
---|---|
To: | Cedar Cox <cedarc(at)visionforisrael(dot)com> |
Cc: | Jan Wieck <JanWieck(at)Yahoo(dot)com>, <pgsql-sql(at)postgresql(dot)org> |
Subject: | Re: REFERENCES constraint |
Date: | 2001-08-12 19:42:47 |
Message-ID: | Pine.LNX.4.30.0108122136370.714-100000@peter.localdomain |
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Thread: | |
Lists: | pgsql-sql |
Cedar Cox writes:
> CREATE TABLE obj_weights (
> object_id int4 REFERENCES ( apple_objects(id) OR banana_objects(id) )
> weight float4,
> )
The way I would work this out is like this:
CREATE TABLE fruit_objects (
object_id serial PRIMARY KEY,
fruit_type text CHECK (fruit_type IN ('apple', 'banana')),
weight float4,
... other common fruit properties ...
);
CREATE TABLE apple_objects (
object_id integer REFERENCES fruit_objects,
color text,
... more apple properties ...
);
CREATE TABLE banana_objects (
object_id integer REFERENCES fruit_objects,
curvature real,
... other banana properties ...
);
--
Peter Eisentraut peter_e(at)gmx(dot)net http://funkturm.homeip.net/~peter
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