From: "Announce" <truthhurts@insightbb.com>
To: <pgsql-sql@postgresql.org>
Subject: DEFAULT Constraint based on table type?
Date: Mon, 28 Nov 2005 14:22:49 -0600
Message-ID: <KBEKKNMFLELKGIADDEPEMEBPCDAA.truthhurts@insightbb.com>
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In-Reply-To: <ECOWS01MpB9pbKWZfEA0000693e@smtp-out1.blueyonder.co.uk>

Lets say I have the following tables.

CREATE TABLE animals(id primary key, name varchar, type varchar);
CREATE TABLE dogs (breed varchar)            INHERITS (animals);
CREATE TABLE birds (bool hasFeathers) INHERITS (animals);

Is there a way I can specify a default on the child table that will populate
the 'type' column? For example, if I am inserting a row in table DOGS, I
would always want the default value for column TYPE to be 'DOG'. If I am
inserting into BIRDS.... type 'BIRD'.

I know that I could add individual triggers on each table that set the TYPE
field to a default value on insert but I wanted a more simple solution like
setting a DEFAULT table-constraint.

Also, In java, this could be done on a parent object by overriding a
constructor or method, using the Class object or instanceof.  Is there
anyway for a table to "know" it's "class" in this scenario?

Thanks,

-Aaron