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Thread: libpq request results

libpq request results

From
"Michael GUIARD"
Date:
Hi !

I hope I choose the correct mailing list and I hope my question has not been already asked.
Correct me if I wrong.
I do not understand something : what is the difference between this mailing list and the newsgroup : news.postrgesql.org ?
My question concerning postgre sql libpq :

I'd like to use database support in my application. My application are
written in C++ and oftenly I do not use complex database.
So I want to use libpq library to manage db from my applications.

When I make a request like SELECT ... the result is downloaded completely
through network. The problem is that I have to wait the end of the download
before viewing some results (for many result rows and with a poor network
connection I have to wait a lot). I tried to use anychronous methos but the
problem is the same : my application is not locked during result retreiving
(good) but I can't present any results until the download is finished.

Is it possible to ask Postgre engine for a request, then wait for the end of
the request : postgre gives me the total result rows and then ask for
downloading the rows separately ?

thanks
Mike

Re: libpq request results

From
"Magnus Hagander"
Date:
> Hi !
>
> I hope I choose the correct mailing list and I hope my
> question has not been already asked.
> Correct me if I wrong.
> I do not understand something : what is the difference
> between this mailing list and the newsgroup : news.postrgesql.org ?

They are mirrored to each other, I beleive. So just different transports
of the same data.


> My question concerning postgre sql libpq :

Postgres or PostgreSQL, please, no such thing as postgre.


> Is it possible to ask Postgre engine for a request, then wait
> for the end of the request : postgre gives me the total
> result rows and then ask for downloading the rows separately ?

Not directly. But what you can do is use a server side cursor, and then
fetch one (or a couple) of rows at a time. It should give you
approximatly the same result. See
http://www.postgresql.org/docs/8.0/static/sql-fetch.html.

//Magnus