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Date: Thu, 2 Jun 2011 17:32:15 +0300
From: Pavel Golub <pavel@microolap.com>
Reply-To: Pavel Golub <pavel@gf.microolap.com>
Organization: Microolap
X-Priority: 3 (Normal)
Message-ID: <11417115.20110602173215@gf.microolap.com>
To: Andrew Chernow <ac@esilo.com>
CC: Pavel Golub <pavel@microolap.com>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>,
	<pgsql-interfaces@postgresql.org>
Subject: Re: [HACKERS] PQdeleteTuple function in libpq
In-Reply-To: <4DE79A58.4010608@esilo.com>
References: <147534417.20110601184310@gf.microolap.com>
	<4DE6A5B7.2070700@esilo.com>
	<707574086.20110602112826@gf.microolap.com>
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Hello, Andrew.

You wrote:

AC> On 6/2/2011 4:28 AM, Pavel Golub wrote:
>> Hello, Andrew.
>>
>> You wrote:
>>
>> AC>  On 6/1/2011 11:43 AM, Pavel Golub wrote:
>>>> Hello.
>>>>
>>>> I'm some kind of PQdeleteTuple function will be very usefull in libpq.
>>>> Because right now after deleting some record I need refetch result
>>>> set, or mark tuple as deleted and this is headache for me.
>>>>
>>
>> AC>  IMHO, this should be handled by the application.  You could track tuples
>> AC>  removed in an int[] or copy the result set into an application defined
>> AC>  array of C structures.  I've always been under the impression that
>> AC>  PGresult objects are immutable once delivered to the application.
>>
>>
>> Andrew, why we have PQmakeEmptyPGresult, PQcopyResult,
>> PQsetResultAttrs, PQsetvalue and PQresultAlloc in this case? Of course
>> there's no big deal with their absence but let's be consistent.
>>

AC> I'm not entirely sure what you are trying to do, but can't you use 
AC> PQmakeEmptyPGresult, PQsetResultAttrs and PQsetvalue to construct a 
AC> result that excludes the tuples you don't want followed by a 
AC> PQclear(initial_result)?


Well, yes. I can. But don't you think it's too complex? Plus such
approach uses twice as much memory. 


-- 
With best wishes,
 Pavel                          mailto:pavel@gf.microolap.com