Re: Basic questions about PQprepare()

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Alexander Farber <alexander(dot)farber(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Basic questions about PQprepare()
Date: 2006-01-28 15:42:45
Message-ID: 11738.1138462965@sss.pgh.pa.us
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Alexander Farber <alexander(dot)farber(at)gmail(dot)com> writes:
> 1) If PQconnectdb fails, do I still need to PQfinish the returned pointer?

Yes, if you don't want to leak memory.

> 2) Similar, if PQprepare fails, do I still need to PQclear its result?

Yes, if you don't want to leak memory.

> 3) Do I have to PQclear(res) inbetween if I want to prepare another query?

They are not comparable actions --- you can do them in either order. In
practice though I don't see why you wouldn't PQclear the result of a
PREPARE as soon as you'd checked that it wasn't conveying an error.

> 4) How do I set the last PQprepare argument, the const Oid *paramTypes?

You'd need to look up the OIDs of the parameter types. In practice it's
usally a lot easier to write the queries so that the parameter types can
be inferred by the backend.

regards, tom lane

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