Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

retrieving resultset of unknow column size

Posted on 2002-07-22
4
Medium Priority
?
311 Views
Last Modified: 2010-03-31
Hi,

i'm creating a web page which displays results for a given query.  The thing is that the query will be entered in a free form field so I have no knowledge how many columns are going to be retrieved from the query.  

i.e.
i wouldn't now if the query is:

select name, last_name from user_table  ( returns two columns)
or
select name from user_table (returns on column)

The question is: how do I retrieve the column names of the resultset? or maybe just how many columns there are.

I basically need to be able to retrieve the data using say rs.getObject("someName"); and display them.

thanks,
- tekel
0
Comment
Question by:tekel
  • 2
4 Comments
 
LVL 18

Accepted Solution

by:
bobbit31 earned 200 total points
ID: 7169741
you can use ResultSetMetaData:

rsmd = rs.getMetaData();

for (int i=0;i<rsmd.getColumnCount;i++) {
   System.out.println(rsmd.getColumnname(i));
}
0
 
LVL 7

Expert Comment

by:Igor Bazarny
ID: 7169918
Hi,

Does this piece of code helps?

    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws IOException, ServletException
    {
        response.setContentType("text/html");
        PrintWriter writer = response.getWriter();
        openPage(writer);
        topHeader(writer);
        Connection connection = null;
        try{
            connection = openConnection();
            Statement invoker = connection.createStatement();
            ResultSet allData = invoker.executeQuery("select * from element");
            ResultSetMetaData cols = allData.getMetaData();
            writer.println("<table>");
            int total = cols.getColumnCount();
            writer.println("<tr>");
            for( int i = 1; i<=total; ++i){
                writer.print("<th>"+cols.getColumnLabel(i)+"</th>");
            }
            writer.println("</tr>");
            writer.println("<tr>");
            while( allData.next() ){
                for(int i=1; i<=total; ++i){
                    writer.print("<td>"+allData.getObject(i)+"</td>");
                }
            }
            writer.println("</tr>");
            writer.println("</table>");
        }
        catch(Exception err){
            writer.println("<pre>");
            err.printStackTrace(writer);
            writer.println("</pre>");
        }
        finally{
            if( connection != null ){
                try{ connection.close(); }catch(SQLException ignore){}
            }
        }
        closePage(writer);
    }

Regards,
Igor Bazarny,
Brainbench MVP for Java 1
0
 

Author Comment

by:tekel
ID: 7169980
thanks a lot, bobbit31
0
 
LVL 18

Expert Comment

by:bobbit31
ID: 7169984
no prob :)
0

Featured Post

Hire Technology Freelancers with Gigs

Work with freelancers specializing in everything from database administration to programming, who have proven themselves as experts in their field. Hire the best, collaborate easily, pay securely, and get projects done right.

Question has a verified solution.

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

This was posted to the Netbeans forum a Feb, 2010 and I also sent it to Verisign. Who didn't help much in my struggles to get my application signed. ------------------------- Start The idea here is to target your cell phones with the correct…
Java functions are among the best things for programmers to work with as Java sites can be very easy to read and prepare. Java especially simplifies many processes in the coding industry as it helps integrate many forms of technology and different d…
This tutorial explains how to use the VisualVM tool for the Java platform application. This video goes into detail on the Threads, Sampler, and Profiler tabs.
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …
Suggested Courses

824 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