This is true, with JDBC 2.0. However, it's not necessarily a good idea.
With many databases, including Oracle, there is no standard way of
retrieving the total number of records returned. Scrollable ResultSets
often involve a large amount of on-system result caching, a substantial
increase in server resource requirements, or both. Essentially, you're
looping anyway.
For some applications this might be ok, but for performance-sensitive web
applications, I suggest avoiding it where possible. One trick when you're
displaying the results of a query and want to put the number of records at
the top is to write your results into a StringBuffer, keeping a count as
you go, writing the count to your PrintWriter, and then writing the
StringBuffer to the writer. That way you don't loop twice.
At 11:55 AM 7/19/2000 -0400, you wrote:
>To get the number of records without looping:
>
>If you are using a jdbc 2.0 driver and your cursor is not TYPE_FORWARD_ONLY,
>you can do:
>
>rs.last(); //moves the cursor directly to the last row
>int num_rows = rs.getRow(); //gets the row number--since it is at the last
>row, this will be the number of records
>rs.beforeFirst(); //move the cursor back to its initial position of
>immediately before the first row
>
>-----Original Message-----
>From: A mailing list for discussion about Sun Microsystem's Java Servlet
>API Technology. [mailto:[EMAIL PROTECTED]]On Behalf Of
>William Crawford
>Sent: Wednesday, July 19, 2000 11:22 AM
>To: [EMAIL PROTECTED]
>Subject: Re: database Search with the servlets and sql.
>
>
>At 11:41 AM 7/19/2000 +0530, you wrote:
> >database Search with the servlets.
> >Can you please sort my issue.
> >
> >1. what method is there to count the no. of records in a resultset(
> >direct method with out looping).
>
>There is no such method. Either run a second query that returns a count(*)
>of results, or loop. The databases don't always provide this data, so JDBC
>can't either.
>
> >2. what is the syntax of 'like' in the below line.
> >
> > String str1="select * from TableInd where Detail like '"+%kw[0]%+"'";
> >
> >context: I have a search box in a form and visitor can enter keywords in
> >the search box(text box). the key word information is tokenized and put
> >in an array kw[numtokens] (num Tokens is Number of tokens entered in hte
> >search box)
> >I want to check the 'Detail' field with the workds matching 'kw[0]';
> >the above is giving error.
>
>Try putting the % characters within your string. That should compile.
>---
>William Crawford + 01 617 577 7844
>Invantage, Inc [EMAIL PROTECTED]
>
>___________________________________________________________________________
>To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
>of the message "signoff SERVLET-INTEREST".
>
>Archives: http://archives.java.sun.com/archives/servlet-interest.html
>Resources: http://java.sun.com/products/servlet/external-resources.html
>LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
>
>___________________________________________________________________________
>To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
>of the message "signoff SERVLET-INTEREST".
>
>Archives: http://archives.java.sun.com/archives/servlet-interest.html
>Resources: http://java.sun.com/products/servlet/external-resources.html
>LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
---
William Crawford + 01 617 577 7844
Invantage, Inc [EMAIL PROTECTED]
___________________________________________________________________________
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff SERVLET-INTEREST".
Archives: http://archives.java.sun.com/archives/servlet-interest.html
Resources: http://java.sun.com/products/servlet/external-resources.html
LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
