Re: Cursornames - Mailing list pgsql-jdbc

I looked a little bit more closely into this matter and Kim's patch
seems correct to me.  We do need better comments or to refactor the code
to make this logic clearer.

What _I think_ happens is that we attempt to create a cursor for
implementing the fetch size but sometimes this is not possible.  For
instance, the query is itself creating a cursor (a DECLARE statement) or
there are multiple queries (statements separated by ';').

As setFetchSize() is just a hint for the driver (it does not _need_ to
consider it), the driver uses the original statement and fetches the
whole lot (the complete result set).  In this case the statement name is
null.

I would just move the test to right after the test to fetchsize and
explain the situation in a comment.

Regards to all,
Fernando

P.S.: Which means that we indeed should not generate an exception if we
cannot create the cursor as I originally thought.



Kim Ho wrote:
> This fixes the behaviour that Felipe Schnack noticed.
>
> The logic goes, if the statement name is null (which happens when you do
> not use cursors or server prepared statements), then we have already
> fetched all the rows, and there are no more.
>
> Cheers,
>
> Kim
>
>
> ------------------------------------------------------------------------
>
> Index: org/postgresql/jdbc1/AbstractJdbc1ResultSet.java
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/interfaces/jdbc/org/postgresql/jdbc1/AbstractJdbc1ResultSet.java,v
> retrieving revision 1.13
> diff -c -p -r1.13 AbstractJdbc1ResultSet.java
> *** org/postgresql/jdbc1/AbstractJdbc1ResultSet.java    30 Jun 2003 21:10:55 -0000    1.13
> --- org/postgresql/jdbc1/AbstractJdbc1ResultSet.java    4 Aug 2003 21:32:11 -0000
> *************** public abstract class AbstractJdbc1Resul
> *** 131,136 ****
> --- 131,138 ----
>               String[] binds = new String[0];
>               // Is this the correct query???
>               String cursorName = statement.getStatementName();
> +             if (cursorName == null)
> +                 return false;
>               sql[0] = "FETCH FORWARD " + fetchSize + " FROM " + cursorName;
>               QueryExecutor.execute(sql,
>                                     binds,
>
>
> ------------------------------------------------------------------------
>
>
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--
Fernando Nasser
Red Hat Canada Ltd.                     E-Mail:  fnasser@redhat.com
2323 Yonge Street, Suite #300
Toronto, Ontario   M4P 2C9