Thread: RE: Why?? executeQuery() & exception: "No results were ret urned by the query."
RE: Why?? executeQuery() & exception: "No results were ret urned by the query."
From
Joe Shevland
Date:
In all the years I've been using the PostgreSQL JDBC driver I haven't
spotted this problem; resultset.next() should just return 'false' if there
are no more rows to retrieve... unless this is caused by executing a
'non-query' i.e. executing an insert/update/delete statement in
sment.executeQuery().
Cheers,
Joe
> -----Original Message-----
> From: pgsql-jdbc-owner@postgresql.org
> [mailto:pgsql-jdbc-owner@postgresql.org]On Behalf Of Panu Outinen
> Sent: Wednesday, 9 May 2001 12:05 AM
> To: pgsql-jdbc@postgresql.org
> Subject: [JDBC] Why?? executeQuery() & exception: "No results were
> returned by the query."
>
>
> Hi there !
>
> Can anyone explain why does executeQuery() throws an exception
> "No results were returned by the query."
> when result set is empty ???????
>
> In my opinion (and also e.g. Oracle's JDBC driver's opinion)
> that this is
> just normal and user can check the number of rows (=0) that none was
> returned. It's totally different to make a query where
> something is wrong
> in the query itself e.g. non-existant column is used or
> perhaps in the
> database connection!
>
> This is "pain in the *ss" to test against in one's code for
> every different
> JDBC driver's DIFFERENT return string there available and
> it's impossible
> to do code that works for even unknown drivers. And
> Postgresql has even
> language dependant versions of this !!!
>
> Since Postgresql source code is so nicely publicly available
> (thank you all
> there!) and thus improvements are easily given by anyone I
> just wonder if
> this could be improved, please !!!
>
> - Panu
>
> PS. I know for sure that at least SQL Server throws the
> following when used
> through JDBC-ODBC bridge: "No ResultSet was produced".
>
>
> ----------------------------------------------------------------------
>
> org\postgresql\jdbc2\Statement.java:
>
> ...
> /**
> * Execute a SQL statement that retruns a single ResultSet
> *
> * @param sql typically a static SQL SELECT statement
> * @return a ResulSet that contains the data produced
> by the query
> * @exception SQLException if a database access error occurs
> */
> public java.sql.ResultSet executeQuery(String sql)
> throws SQLException
> {
> this.execute(sql);
> while (result != null &&
> !((org.postgresql.ResultSet)result).reallyResultSet())
> result = ((org.postgresql.ResultSet)result).getNext();
> if (result == null)
> throw new PSQLException("postgresql.stat.noresult");
> return result;
> }
> ...
>
> ----------------------------------------------------------------------
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
>