How can we check whether a ResultSet is EMPTY or NOT ?

Question

i'm getting some data inside ResulSet (using JDBC inside Servlet).
now i want to redirect response according to ResultSet...., if ResultSet is EMPTY then on diff page, else on different page...
how can i check whether a ResultSet is empty or not...
i've used next() , wasNull() methods ,,, but not solving the purpose...
thanx in advance...

Answer 1

What you could do is to ask the database fora
record count and check that for zero.
How?????You just do an SQL statement but instead of the list of fields after SELECT you put
SELECT count(*) FROM ...... WHERE .....
That returns a single integer value into the resultset giving the number of matching records currently in the database.
The trouble is you can't be certain that when you subsequently access the records the number won't have changed, because databases are generally accessible to more than one process at a time and some other process might add or delete a record between counting and retrieving or, for that matter, during the process of retrieval.
Also the count is likely to take more time than just doing rs.next() and seeing if you get a record.
Since you seem to be in a servlet environment you should consider doing the database query and the first rs.next() at the top of the servlet/JSP that presents the results and, if there are no records, using getServletContext.getRequestDispatcher(...).forward(request, response) to swich to your error page if it returns false.
So the stucture looks like:
rs = stmt.executeQuery(......);
if(!rs.next())
      getServletContext().getRequestDispatcher("/noresultspage.jsp").forward(request, response);
else {
     do   {
         .... display result data
      } while(rs.next());
    }