Re: next value expression - Mailing list pgsql-hackers

From Tom Lane
Subject Re: next value expression
Date
Msg-id 18666.1038417854@sss.pgh.pa.us
Whole thread Raw
In response to Re: next value expression  (Neil Conway <neilc@samurai.com>)
Responses Re: next value expression  (Neil Conway <neilc@samurai.com>)
List pgsql-hackers
Neil Conway <neilc@samurai.com> writes:
> On Wed, 2002-11-27 at 10:29, Manfred Koizar wrote:
>> By accident I stumbled across the following paragraph in the August
>> 2002 draft of SQL 2003:
>> 
>> If there are multiple instances of <next value expression>s
>> specifying the same sequence generator within a single
>> SQL-statement, all those instances return the same value for a
>> given row processed by that SQL-statement.
>> 
>> Is this of any relevance to PG's nextval()?

> Somewhat -- SQL2003 defines sequence generators that are pretty much
> identical in functionality to PostgreSQL's sequences, although the
> syntax is a bit different.

I would think his point is that the above paragraph specifies behavior
that is very definitely NOT like Postgres'.

> I submitted a patch for 7.4 that adjusts the
> CREATE SEQUENCE grammar to match SQL2003's CREATE SEQUENCE a little more
> closely,

Did we apply it?  I'm inclined not to, until we nail down the semantic
implications a little more.  Conforming to the spec on syntax when we
don't on semantics strikes me as a bad idea.
        regards, tom lane


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