Checking for empty resultset

[Tom Joiner]

I am running a SQL query which is like this:

   select_from_account = "SELECT * FROM account WHERE username = " + username;
   rs = statement.executeQuery(select_from_account);
// check for empty here and do something
   while (rs.next()) {
// do something
    }  

And I want to check if the resultset is empty. Looking through the API here:

http://java.sun.com/j2se/1.3/docs/api/java/sql/ResultSet.html

I don't see the obvious solution. I can of course walk through the resultset twice, the first time counting it, and the second time using it, but this seems like a waste. Is there an API call that returns if it is empty?

[Paul Sturrock]

rs.next() returns false when the cursor can't move forward. So:

boolean isEmpty = true;
while (rs.next()) {
    isEmpty = false;
    // do stuff
}
if (isEmtpy) {
    // do stuff
}

[Shailesh Chandra]

Just want to add one thing when you call rs.next() takes you to first row, make sure you do not call rs.next() again until you have retrieved value of all columns of first row.


Shailesh