From: Jon Barnett <jbarnett@pobox.com>
To: 'Peter Mount' <petermount@it.maidstone.gov.uk>
To: 'pgsql-interfaces@hub.org' <pgsql-interfaces@hub.org>
Subject: RE: [INTERFACES] JDBC next() method
Date: Thu, 15 Apr 1999 00:37:03 +1000
Message-ID: <01BE86D8.15D52260.jbarnett@pobox.com> (raw)
On Wednesday, 14 April 1999 23:18, Peter Mount
[SMTP:petermount@it.maidstone.gov.uk] wrote:
> This looks ok.
>
> queryResult is null if there was an error in the query, so you should
> check for that.
>
> However, normal use would have the result parsed within a
> while(queryResult.next()) {} loop, so your interpretation is correct.
I don't think the query should give an error - as the query is at least
syntactically correct. Certainly, if I check for a queryResult == null, the
condition doesn't occur for an empty table.
I just had a quick browse on some old JDBC notes and it looks like the correct
solution is:
queryResult = dbStatement.executeQuery("select max(history_id) from history");
queryResult.next();
nextID = queryResult.getLong(1) + 1;
if (queryResult.wasNull())
nextID = 0;
Note: queryResult.wasNull() only works immediately after calling a getxxx
method.
Thanks.
JonB.
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To: pgsql-interfaces@postgresql.org
Cc: jbarnett@pobox.com, petermount@it.maidstone.gov.uk, pgsql-interfaces@hub.org
Subject: RE: [INTERFACES] JDBC next() method
In-Reply-To: <01BE86D8.15D52260.jbarnett@pobox.com>
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