Re: JDBC stored procs doc patch - Mailing list pgsql-jdbc

From Fernando Nasser
Subject Re: JDBC stored procs doc patch
Date
Msg-id 3F27E338.5090008@redhat.com
Whole thread Raw
In response to JDBC stored procs doc patch  (Nic <nferrier@tapsellferrier.co.uk>)
Responses Re: JDBC stored procs doc patch  (Nic <nferrier@tapsellferrier.co.uk>)
List pgsql-jdbc
Hi Nic,

It is great to see someone trying to improve the documentation.

I have a few questions about the first part (about fetch size):



> +
> +     <para>Changing code to cursor mode is as simple as setting the
> +       fetch size of the <classname>Statement</classname> to the
> +       appropriate size. Setting the fecth size back to 0 will cause
> +       all rows to be cached (the default behaviour).
> +

Perhaps you should mention the retrieval all rows must happen inside a
transaction.  The cursor that is created is not HOLD or anything.


> +<programlisting>
> +Statement st = db.createStatement();
> +// Turn use of the cursor on.
> +st.setFetchSize(50);
> +ResultSet rs = st.executeQuery("SELECT * FROM mytable");
> +while (rs.next()) {
> +   System.out.print("a row was returned.");
> +}
> +rs.close();
> +// Turn the cursor off.
> +st.setFetchSize(0);
> +ResultSet rs = st.executeQuery("SELECT * FROM mytable");
> +while (rs.next()) {
> +   System.out.print("many rows were returned.");
> +}
> +rs.close();
> +// Close the statement.
> +st.close();
> +</programlisting>
> +     </para>
> +
> +


I do not understand what the example is supposed to show.  The fetch
size is transparent to the user (it is just a hint to the driver about
what should be the best strategy) so you should be able to get all the
rows, and the same number of them, as you go doing rs.next().


Regards,
Fernando



--
Fernando Nasser
Red Hat Canada Ltd.                     E-Mail:  fnasser@redhat.com
2323 Yonge Street, Suite #300
Toronto, Ontario   M4P 2C9


pgsql-jdbc by date:

Previous
From: Kim Ho
Date:
Subject: SetFetchSize and SetFetchDirection
Next
From: Nic
Date:
Subject: Re: JDBC stored procs doc patch