From: | "G(dot)Nagarajan" <gnagarajan(at)dkf(dot)de> |
---|---|
To: | <pgsql-jdbc(at)postgresql(dot)org> |
Subject: | jdbc cursor positioning |
Date: | 2002-10-06 14:50:07 |
Message-ID: | NFBBIOPECKPCJJHHBOGJOELJDIAA.gnagarajan@dkf.de |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | Postg배트맨 토토SQL : Postg배트맨 토토SQL 메일 링리스트 : 2002-10-06 이후 PGSQL-JDBC 14:50 |
hi,
I am trying to implement "page wise" selection of rows
from a table. The table contains around 10000 rows and
I will be displaying only 10 rows at a time. At any time
I might have to display say the 5th page or 45th page etc.
After searching in the archives, I came across this solution:
<sample>
c.setAutoCommit (false);
Statement stmt = c.createStatement ();
stmt.execute ("declare " + CURSOR_NAME + " cursor for select * from
huge_table");
stmt.close ();
PreparedStatement fetch = c.prepareStatement ("fetch ? from " +
CURSOR_NAME);
PreparedStatement move = c.prepareStatement ("move ? in " + CURSOR_NAME);
fetch.setInt (1, 100);
ResultSet rs = fetch.executeQuery ();
...
fetch.setInt (1, -100);
rs = fetch.executeQuery ();
move.setInt (200);
int actuallyMoved = move.executeUpdate ();
if (actuallyMoved < 200)
System.out.println ("Less then 200 rows in cursor");
...
c.commit (); //Will also close the cursor(s)...
</sample>
The statement "move? ..." gives an error if executed. This command gives not
results and therefore I cannot use a executeUpdate() with it. It tells that
the update count could not be determined. So my questions are
1-> has the cursor been actually moved irrespective of the error?
2-> are there any other ways of positioning the cursor.
3-> is there any way by which i can know what is the current position?
Obviously i can give fetch() n times, but if the user selects the 400th
page then the driver will retrieve 400*10 records!
any suggestions are most welcome,
Regards,
Nagarajan.
From | Date | Subject | |
---|---|---|---|
Next Message | Toby | 2002-10-06 19:27:13 | Re: jdbc cursor positioning |
Previous Message | Chris Thompson | 2002-10-06 13:30:08 | Re: jdbc problem with multiple connections |