On November 21, 2002 06:04 pm, you wrote:
> Hi,
>
> Your revised solution is a good idea however it will not work with an ORDER
> BY clause in the SQL statement. We use Oracle here and originally that was
> what I wanted to do but I found through much experimentation and consulting
> the Oracle docs that Oracle will first return the rows up to and/or
> including what was specified for the ROWNUM setting and THEN it does the
> ORDER BY!
>
> So what ends up happening is you find yourself missing some rows that you
> feel should be there such as when you run the statement without the ROWNUM
> clause using the ORDER BY and vice-versa.
>
> You can confirm this behaviour by applying the ROWNUM and ORDER BY clauses
> independent of each other or in different combinations in the original SQL
> statement to see what I'm trying to explain here.
>
> HTH,
> Greg.
>
Good point. I forgot about that.
But you can do the same thing by stopping the loop via the extra condition in
the while loop.
>
> Similarily, you could change the while loop from:
> -- <snip> ---
>
> > while (rs.next()) {
> > nNumRows++;
> >
> > if ( (nNumRows >= p_nStartRow) && (nNumRows <
> > p_nStartRow + p_nMaxRows) ) {
> > // Populate our transaction list objects
> > TransactionList transactionlist = new
> > TransactionList(rs.getString(3), rs.getString(5),
> > rs.getInt(6), rs.getString(7),
> > rs.getString(8),
> > rs.getBigDecimal(9, 2), rs.getBigDecimal(10, 2),
> > rs.getBigDecimal(11, 2), rs.getBigDecimal(12, 4),
> > rs.getBigDecimal(13, 4), rs.getBigDecimal(14, 4),
> > rs.getString(15), rs.getString(17),
> > rs.getString(22),
> > rs.getLong(1), rs.getString(19),
> > rs.getString(23), rs.getString(24),
> > rs.getString(25));
> > vData.addElement(transactionlist);
> > }
> > }
>
> --- <end snip> ----
>
> To:
> _-- <snip> ---
>
> > while (rs.next() && (nNumRows < p_nStartRow +
>
> p_nMaxRows)) {
> --- cut (rest of the loop is the same) -----
>
> to do the same thing without the pseudo column.
>
> Someone else had reply about a scrollable resultset which might be more
> effiecient than this solution, but I have no experience with that.
>
> Hope this helps,
> Don Brown
>
> On November 21, 2002 11:56 am, [EMAIL PROTECTED] wrote:
> > Ok guys I'm giving you all a gift.... I had the same problem
>
> understanding
>
> > how PetStore does it and after reading much documentation on the design
> > pattern and various other people's implementation of said pattern here is
> > my interpretation of the Page-by-Page Iterator pattern...
> >
> > This is actually still being used in production for a project developed
> > from three years ago so I know it works... Don't give me a hard time
>
> about
>
> > using a Vector though... If you want to use an ArrayList instead by all
> > means feel free to change it!
> >
> > Debug is a class I wrote for outputting values while developing/unit
> > testing so implement your own such as Log4J or whatever. I'ved also
>
> removed
>
> > the bulk of the SQL statement as it is somewhat proprietary but I think
>
> you
>
> > will get the drift...
> >
> > --- <Code is in original reply from [EMAIL PROTECTED]> ---
>
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