Subject: Re: ENUM like data type
From: Scott Marlowe <smarlowe@g2switchworks.com>
To: =?ISO-8859-1?Q?Mart=EDn_Marqu=E9s?= <martin@bugs.unl.edu.ar>
Cc: PFC <lists@boutiquenumerique.com>,
	Mike Rylander <mrylander@gmail.com>, pgsql-sql@postgresql.org
In-Reply-To: <200506281522.25124.martin@bugs.unl.edu.ar>
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	<200506281522.25124.martin@bugs.unl.edu.ar>
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Date: Tue, 28 Jun 2005 13:46:18 -0500

On Tue, 2005-06-28 at 13:22, Mart=C3=ADn Marqu=C3=A9s wrote:
> El Mar 28 Jun 2005 13:58, PFC escribi=C3=B3:
> >=20
> > >> Here is where I get uncertain as to if this is possible. My idea is =
to
> > >> create a pseudo type that triggers the creation of it's lookup table=
s
> > >> the same way the SERIAL type triggers creation of a sequence and ret=
urns
> > >> an int with the right default value.
> >=20
> > 	Personnally I use one table which has columns (domain, name) and which=
 =20
> > stores all enum values for all different enums.
> > 	I have then CHECK( is_in_domain( column, 'domain_name' )) which is a =20
> > simple function which checks existence of the value in this domain (SEL=
ECT =20
> > 1 FROM domains WHERE domain=3D$2 AND name=3D$1 LIMIT 1) for instance.
> > 	You can also use integers.
>=20
> I personally think that the ENUM data type is for databases that are not =
well=20
> designed. So, if you see the need for ENUM, that means you need to re-thi=
nk=20
> your data design.

I would generally agree, however, a pseudo type like serial that created
the properly fk'd table with all the options in it would be quite nice
to have.