Re: How can I retrieve double or int data type for libpq

From: Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
To: a <372660931(at)qq(dot)com>, pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: How can I retrieve double or int data type for libpq
Date: 2018-06-13 04:29:51
Message-ID: 1528864191.2657.11.camel@cybertec.at
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a wrote:
> I wanna use C library to connect pgsql server and I got 2 questions:

This is all well documented in
https://www.postgresql.org/docs/current/static/libpq.html

> 1, If I can fetch a row's data instead of using PQgetvalue?

PGgetvalue *is* the way to fetch the row's data.

There is no call to fetch *all* columns at once, but that is
not necessary.

> 2, PQgetvalue will return all data as text, I would have to convert them into the
> relative data type, is there a way of getting data by its original format?

You will get the data in binary form if you specify a resultFormat of 1
with PQexecParams.

Note, however, that they will be in the native binary format of the *server*.

Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com

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