Date: Tue, 04 Oct 2005 19:54:47 -0400
From: Ferindo Middleton Jr <fmiddleton@verizon.net>
Subject: Re: Why doesn't the SERIAL data type automatically have a
In-reply-to: <43430EEB.80500@archonet.com>
To: Richard Huxton <dev@archonet.com>
Cc: "Jim C. Nasby" <jnasby@pervasive.com>,
	Scott Marlowe <smarlowe@g2switchworks.com>,
	Tom Lane <tgl@sss.pgh.pa.us>, pgsql-sql@postgresql.org
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Richard Huxton wrote:
> Jim C. Nasby wrote:
>>>>> Is there some reason why the SERIAL data type doesn't 
>>>>> automatically have a UNIQUE CONSTRAINT.
>>>>
>>>> It used to, and then we decoupled it.
> [snip]
>> Arguably it would have been better to make the default case add either
>> UNIQUE or PRIMARY KEY with a way to over-ride.
>
> Arguably SERIAL shouldn't be a type at all since it's nothing to do 
> with defining a set of values. If you were being clean about it you'd 
> have to have something like "mycol INTEGER SERIAL UNIQUE", then wire 
> SERIAL to a generator function for the type in question.
>
>> If newbies are getting burned maybe it would be useful to toss a NOTICE
>> or maybe even WARNING when a serial is created without a unique
>> constraint of some kind?
>
> Don't forget the NOT NULL too. Perhaps simpler to have a PGIDENT 
> pseudo-type that implies "UNIQUE NOT NULL" and then explain the 
> difference in the docs.
>
> -- 
>   Richard Huxton
>   Archonet Ltd
>
I like Richard's idea. That seems to be the best way to go.

Ferindo
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