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Date: Tue, 4 Feb 2025 22:41:38 +0100 (GMT+01:00)
From: Thiemo Kellner <thiemo@gelassene-pferde.biz>
To: "pgsql-generallists.postgresql.org" <pgsql-general@lists.postgresql.org>
Message-ID: <64603f36-b6d5-469b-8d6d-30376842241b@gelassene-pferde.biz>
In-Reply-To: <628D4022-5365-4D00-810B-10349A90874A@kleczek.org>
References: <c0fe3bc0-efb2-4648-ac9a-435601acc2bf@gelassene-pferde.biz>
 <628D4022-5365-4D00-810B-10349A90874A@kleczek.org>
Subject: Re: Lookup tables
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04.02.2025 18:31:09 Micha=C5=82 K=C5=82eczek <michal@kleczek.org>:

>=20
>> On 4 Feb 2025, at 18:27, Thiemo Kellner <thiemo@gelassene-pferde.biz> wr=
ote:
>>=20
>> =EF=BB=BF Unless the lookup table is actually a check constraint one can=
 use to populate dropdown boxes in an interface.
>=20
> That is even worse because it ceases being transactional and users might =
select something different than what they see on the screen.

I might see what you want to point out. E.g. the table is COLOURS. The rec =
with id 1 is RED, the one with id 2 is BLUE, 3 is GREE and so on. Now you l=
oad these values into the dropdown box that sports RED, BLUE, GREE and so o=
n. While someone selects GREE, there is a maintenance release changing GREE=
 to YELLOW. So when that someone sends the selection by id to the backend, =
not GREE is selected but YELLOW.

A) Your release changed the sementics of the record 3. It's meaning changed=
. I cannot recommend doing that.
B) If you absolutely must change the semantic, put your application into ma=
intenance mode in which noone can select anything beforehand.

If the maintenance would just correct the typo from GREE to GREEN, nothing =
would happen. Yor customer still ordered the lavishly green E-Bike her hear=
 ever desired.