Re: Proposal: Solving the "Return proper effected tuple count

From: Steve Howe <howe(at)carcass(dot)dhs(dot)org>
To: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc: Joe Conway <mail(at)joeconway(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Proposal: Solving the "Return proper effected tuple count
Date: 2002-09-09 03:44:37
Message-ID: 4485851027.20020909004437@carcass.dhs.org
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Hello Bruce,

Monday, September 9, 2002, 12:36:38 AM, you wrote:

BM> Joe Conway wrote:
>> Sure, but that's why I am in favor of changing the tag. If you did:
>>
>> DELETE FROM fooview WHERE name LIKE 'Joe%';
>>
>> and got:
>>
>> MUTATED 507324 3
>>
>> it would mean that 3 tuples in total were affected by all of the
>> substitute operations, only of of them being an INSERT, and the Oid of
>> the lone INSERT was 507324. If instead I got:
>>
>> DELETE 0
>>
>> I'd be back to having no useful information. Did any rows in fooview
>> match the criteria "LIKE 'Joe%'"? Did any data in my database get
>> altered? Can't tell from this.

BM> OK. Do any people have INSTEAD rules where there are not commands
BM> matching the original query tag? Can anyone think of such a case being
BM> created?
I can think a thousand cases.
For instance, one could create an update rule that would delete rows
referenced on a second table (to avoid orphan rows). OR a user could
make an insert rule that empties a table with DELETE so that only one
row can always be assumed in that table... the possibilities are
infinite.

BM> The only one I can think of is UPDATE implemented as separate INSERT and
BM> DELETE commands.
I'm afraid the great imagination of PostgreSQL users has come to all
kind of uses and misuses for such a powerful feature :)

-------------
Best regards,
Steve Howe mailto:howe(at)carcass(dot)dhs(dot)org

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