Re: want basic help with C

From: Oliver Elphick <olly(at)lfix(dot)co(dot)uk>
To: Arindam Haldar <arindamhaldar(at)hotpop(dot)com>
Cc: pgsql-interfaces(at)postgresql(dot)org, pgsql-general(at)postgresql(dot)org
Subject: Re: want basic help with C
Date: 2002-05-21 13:31:18
Message-ID: 1021987878.1400.23.camel@linda
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On Tue, 2002-05-21 at 13:34, Arindam Haldar wrote:
> Arindam Haldar wrote:
> hi,
> i went thru the docs on programming interface of postgresql with c. But

This is the libpq interface, yes?

You need to read the libpq reference: chapter 1 of the Programmer's
Guide.

> am unable to understnad to use the interface to query a select
> statement. the database is--->masterdb & in it there is a table
> -->colleges with a few columns & a few records for testing..
> now i want to use a general select statement--> select * from colleges,
> but going thru the docs again & again from different sites am unable to
> undestand how to use it.
> can u gove me a basics to use the funstion to use the same & print the
> rows in the tables

First you have to connect to the database, using PQconnectdb() or a
related function. This returns a handle which you have to use in all
other API calls for this connection.

Send your command or query to the backend with PQExec()
This returns a query handle which you can use to get the results with
the various calls listed in section 1.3.4 of the Programmer's Guide.

Close the connection with PQfinish()

> pls--> i wanted to ask this 2nd Question-->is it necessary to start
> postgreswith option -i too to accept connection from localhost(C
> programme). command line works fine without the said option but unless i
> use -i , i cannot connect to postgres.

If you connect through TCP/IP you always need the -i option on the
postmaster. Connecting with host set to localhost is a TCP/IP
connection. Connecting with host set to nothing connects through a Unix
socket on the local machine; this does not need the -i option.

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C

"O come, let us worship and bow down; let us kneel
before the LORD our maker." Psalms 95:6

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