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Re: Advise on mapping JTable to large PostgreSQL table

From: Andres Olarte <olarte(dot)andres(at)gmail(dot)com>
To: "pgsql-jdbc(at)postgresql(dot)org" <pgsql-jdbc(at)postgresql(dot)org>
Subject: Re: Advise on mapping JTable to large PostgreSQL table
Date: 2005-12-06 22:33:35
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-jdbc
Couldn't you use a single ugly "SELECT *" with a cursor and then fill your
local cache as the client is scrolling through the table?  It will scroll
kind of slow the first time, but then i'll work nice. I'm not very into
Swing, but for that you'd only need the number of rows  with something like
"SELECT count(*)".

On 12/6/05, Kris Jurka <books(at)ejurka(dot)com> wrote:
> On Tue, 6 Dec 2005, Joost Kraaijeveld wrote:
> > I *must* (as in: I have no choice and it can't be solved another way by
> > customer demand) display a large table (> 1.100.000 records) in a JTable
> > ( or something that looks like a JTable for the customer).
> >
> > AS a JTable works with rows, so I have written code that calculates the
> > row of the record in the query and maps any row request to an index in
> > the query.
> >
> > 1. Customer wants the record with 'some text' in column 'a'
> > 2. I calculate the index:
> > select count(*) from table where a < 'some text'
> There's got to be a better way of storing this index.  If this is readonly
> data then you could easily number all of these in the database itself.  I
> think the problem may be that you are trying to index all this data as an
> array where you need an absolute offset.  Perhaps a different data
> structure would make a better backing type?
> > 4. If not, I get 100 records before and after the requested record,
> > including the record itself and put them in the local cache so that
> > JTable can call AbstratTableModel.getValueAt(row,column) without the
> > need of accessing the database.
> How do you determine the records before and after at the moment?
> Kris Jurka
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
>       choose an index scan if your joining column's datatypes do not
>       match

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