[PERFORM] JDBC best practice
I'm using a Postgres table as the data source for a JTable
in a Java app. As a first approximation, I'm implementing
AbstractTableModel.getValueAt() like so:
public Object getValueAt(int row, int col)
{
try
{
rs_.absolute(row + 1);
return rs_.getObject(col + 1);
}
catch (Exception e)
{
...
}
return null;
}
Where rs_ is a RecordSet object. What I'm wondering is
whether it's better to call absolute() or relative() or
next()/previous(). If absolute() is the slowest call,
then I can cache the last row fetched and move relative
to that.
My suspicion is that next()/previous() is much faster
than absolute() when the record to be fetched is very near
the last record fetched. I haven't actually tried it, but
I'd like some insight if others can already answer this
question based on knowledge of the server side and/or the
JDBC driver.
__
David B. Held
Software Engineer/Array Services Group
200 14th Ave. East, Sartell, MN 56377
320.534.3637 320.253.7800 800.752.8129
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Re: [PERFORM] JDBC best practice
On Mon, 28 Mar 2005, Dave Held wrote: I'm using a Postgres table as the data source for a JTable in a Java app. Where rs_ is a RecordSet object. What I'm wondering is whether it's better to call absolute() or relative() or next()/previous(). If absolute() is the slowest call, then I can cache the last row fetched and move relative to that. My suspicion is that next()/previous() is much faster than absolute() when the record to be fetched is very near the last record fetched. I haven't actually tried it, but I'd like some insight if others can already answer this question based on knowledge of the server side and/or the JDBC driver. There are two types of ResultSets that can be returned by the JDBC driver. One is backed by a cursor and can only be used for TYPE_FORWARD_ONLY ResultSets so it is not really applicable to you. The other method retrieves all results at once and stashes them in a Vector. This makes next, absolute, and relative positioning all equal cost. Kris Jurka ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
