Solved

How to find out if there a Database ResultSet contains results

Posted on 1998-07-31
3
187 Views
Last Modified: 2010-03-30
I'm developing a servlet and I need to test whether there are any results in the ResultSet returned from my database query, if there aren't any I want to display an html page which indicates this.
What is the method to determine if there are results, I don't want to use 'next()' as this moves the resultset counter on one.

Please send me the code.

Thanks

Mel
0
Comment
Question by:help_me
  • 2
3 Comments
 
LVL 5

Expert Comment

by:msmolyak
ID: 1229589
I am afraid you have to call next() and cache the row values if the set is not empty.
0
 
LVL 2

Accepted Solution

by:
shchuka earned 50 total points
ID: 1229590
There's no other way to find out if the ResultSet is empty as to call the next() method.  Here's what you can do:

ResultSet = db.executeQuery(...);
if(rs == null) {
    //Error in the query string
}
if(!rs.next()) {
    //ResultSet is empty - do whatever you need
} else {
    do {
        //Do whatever you need with each row
    } while(rs.next());
}

This way you don't loose the first record by using next() to figure out whether the recordset is empty.
0
 
LVL 5

Expert Comment

by:msmolyak
ID: 1229591
Statement.executeQuery() never returns null, a ResultSet object (possibly empty) is always returned.
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
hibernate example issues from command prompt 10 63
Running JavaFX on JDeveloper 12C 1 76
ejb stateless example 2 40
Html split(text) 2 25
An old method to applying the Singleton pattern in your Java code is to check if a static instance, defined in the same class that needs to be instantiated once and only once, is null and then create a new instance; otherwise, the pre-existing insta…
Java had always been an easily readable and understandable language.  Some relatively recent changes in the language seem to be changing this pretty fast, and anyone that had not seen any Java code for the last 5 years will possibly have issues unde…
Viewers will learn about the different types of variables in Java and how to declare them. Decide the type of variable desired: Put the keyword corresponding to the type of variable in front of the variable name: Use the equal sign to assign a v…
Viewers will learn about the regular for loop in Java and how to use it. Definition: Break the for loop down into 3 parts: Syntax when using for loops: Example using a for loop:

679 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question