From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Volker Paul <vpaul@dohle.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: C/C++ interface
Date: Tue, 13 Feb 2001 09:56:27 -0500 (EST)
Message-ID: <200102131456.JAA24367@candle.pha.pa.us> (raw)
In-Reply-To: <3A892433.879F40A0@dohle.com>
Cursors and standard queries are pretty much the same, except the cursor
can control the rows returned.
> Hello,
>
> in the C interface documentation there is an example using:
>
> res = PQexec(conn, "DECLARE mycursor CURSOR FOR select * from
> pg_database");
> if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
> {
> fprintf(stderr, "DECLARE CURSOR command failed\n");
> PQclear(res);
> exit_nicely(conn);
> }
> PQclear(res);
> res = PQexec(conn, "FETCH ALL in mycursor");
>
> ...etc. So the statements are:
>
> DECLARE mycursor CURSOR FOR select * from pg_database;
> FETCH ALL in mycursor;
>
> What's the difference between this and simply doing:
> select * from pg_database;
>
> I tried this in psql, the result seemed the same.
>
> What I'm really using, however, is the C++ interface.
> Its documentation is not yet complete.
> There, too, I tried a version with and without cursor.
> The result seems to be the same, but returned int is always 0
> for the version without cursor, so I get no information whether
> the query succeeded.
>
> Is someone maintaining the C++ interface and its documentation?
>
>
> Thanks,
>
> Volker Paul
>
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 853-3000
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To: pgsql-docs@postgresql.org
Cc: pgman@candle.pha.pa.us, vpaul@dohle.com, pgsql-sql@postgresql.org
Subject: Re: C/C++ interface
In-Reply-To: <200102131456.JAA24367@candle.pha.pa.us>
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