Re: PQdeleteTuple function in libpq

Hello.

So having studied the fe-exec.c sources, I came to this conclusion:
we may just ignore deleted tuple and it will be destroyed by
PQclear automatically, becuase PQclear deals with memory blocks.

int PQdeleteTuple(PGresult *src, int tup_num)
{
if (!src)
return NULL;

int i,
field;

/* Invalid tup_num, must be < ntups */
if (tup_num < 0 || tup_num >= src->ntups)
return FALSE;

for (i = tup_num; i < src->ntups - 1; i++)
{
src->tuples[i] = src->tuples[i + 1];
}
src->ntups--;
return TRUE;
}

I also checked pqAddTuple, PQcopyResult and PQSetValue, they are OK with this
solution.

Am I correct with this?

You wrote:

PG> Hello.

PG> I'm some kind of PQdeleteTuple function will be very usefull in libpq.
PG> Because right now after deleting some record I need refetch result
PG> set, or mark tuple as deleted and this is headache for me.

PG> So I checked fe-exec.c sources and wrote this:

PG> int PQdeleteTuple(PGresult *src, int tup_num)
PG> {
PG> if (!src)
PG> return NULL;

PG> int i,
PG> field;
PG>
PG> /* Invalid tup_num, must be < ntups */
PG> if (tup_num < 0 || tup_num >= src->ntups)
PG> return FALSE;

PG> free(src->tuples[tup_num]);
PG>
PG> for (i = tup_num; i < src->ntups - 1; i++)
PG> {
PG> src->tuples[i] = src->tuples[i + 1];
PG> }
PG> src->ntups--;
PG> return TRUE;
PG> }

PG> But I'm pretty sure, that "free(src->tuples[tup_num])" is bullshit!
PG> Because memory is allocated by pqResultAlloc, which in turn plays with
PG> memory blocks and so on...

PG> Can anyone help me in this?

PG> PS I'm not a C guru, so don't please kick me hard. :)

PG> Thanks.

--
With best wishes,
Pavel mailto:pavel(at)gf(dot)microolap(dot)com