RE: Loading large resultset to a List

["AnanthaRamaiah, Gururaja (CTS)" <AGururaj@xxxxxxxxxxxxxxxx>]

John,
        Even we are using such large lists. We use a Stored procedure
running on AS400 that returns the resultset. 
We display 100 records per page in a new Javascript window. We are providing
Next, Previous and Page Number links on the displayed page. The user can
even search for a product or customer etc. For single selection lists we use
radio buttons and for multiple selections we use check boxes. 
        Every time the user ask for a different page the Stored procedure
will be called which will return the whole resultset. We position the record
pointer to appropriate location and read 100 records from there. I think
this may be of some help to you.

Regards,
Gururaj

        -----Original Message-----
        From:   Alex Garrison [SMTP:agarrison@logtech.com]
        Sent:   Wednesday, May 31, 2000 9:38 PM
        To:     JAVA400-L@midrange.com
        Subject:        Re: Loading large resultset to a List

        John,

        On our system we are using servlets and jsp's to present html to a
client
        browser.  In order to display large lists, we do the following:
        1. build a page of data in a servlet.  Put the info in a bean and
pass to a
        jsp.
        2. jsp displays the page to the client browser.  The displayed page
has
        buttons for page up/down and a place to put in a search field (you
dont want
        to page down through 100,000 employees if you really want to see Mr.
Zero).
        3. Client browser clicks on page down/up or enters search info.
Info is
        sent to the servlet.  Go to step one above.

        This technique works quite well for us.  The servlet doesnt have to
just
        retrieve one page worth of data, by the way.  You can let the
servlet
        retrieve whatever makes sense and hold onto the result set and wait
on the
        page up/down/search from the client.

        This is basically the same technique we have used for years in
building
        subfiles.  Since your subfile in the rpg world can only have 9999
entries,
        you have to handle the page up/down yourself when going through
large lists.

        Alex Garrison

        ----- Original Message -----
        From: "Lee, John" <JLee@lear.com>
        To: <JAVA400-L@midrange.com>
        Sent: Wednesday, May 31, 2000 10:46 AM
        Subject: Loading large resultset to a List


        > Using JDBC, I want to retrieve rows from an employee master file
located
        on
        > a server. These rows I will then load into a List. This List will
then be
        > displayed to the user, where they will position/scroll to the
desired
        > employee.
        > When the number of employees in the database is relatively small,
this is
        > easy. I can retrieve all the rows with one request and then load
the List.
        > However, if the number of employees in the database is very large
(say,
        > 100,000), then I have a problem. Even if I could, I wouldn't want
to
        attempt
        > to retrieve all 100,000 rows and then load them all into the List.
Yet, as
        > the user is repositioning/scrolling through the List, I want it to
appear
        to
        > them that it does contain all 100,000 rows.
        > Is there a commonly accepted way of retrieving/presenting a large
table in
        > this manner? It almost seems that I should be retrieving some new
subset
        of
        > rows each time the user uses the scroll bar or repositions the
list (using
        a
        > text field).
        >
        > I'm not necessarily looking for example code. A few words
outlining how
        one
        > might accomplish this, or suggested links of where I might find
the
        > information, would go along way.
        >
        > Thank you.
        >
        >
        >
        >
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