Java compile error-don't know how to extend class

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March 4th, 2002, 10:33 AM

IrinaIonela

Contributing User

Join Date: Oct 2001

Location: Lisbon

Posts: 45

Time spent in forums: < 1 sec
Reputation Power: 12

Java compile error-don't know how to extend class

I'm trying to extend a class that implements an interface:
: public class relationset extends org.gjt.mm.mysql.Driver

class: org.gjt.mm.mysql.Driver
interface: java.sql.Driver

with the following Java code:

PHP Code:


		
			
 import java.sql.*;

 import java.io.*;



public class relationset extends org.gjt.mm.mysql.Driver

{

    public static ResultSet execQuery() throws SQLException

    {

        try

        {

            Connection databaseConnection = DriverManager.getConnection("jdbc:mysql://172.16.4.39:3306/ssntvjp", "root", "");



            String sqlString = "SELECT * FROM Descriptor D WHERE D.SubDescriptor IS NULL";



            Statement stmt = databaseConnection.createStatement();



            return stmt.executeQuery(sqlString);

        }

        catch(SQLException e)

        {

            throw(e);

        }

    }

}

....but the following error occurs:

.\relationset.java:7: unreported exception java.sql.SQLException; must be caught or declared to be thrown

Can anybody tell-me what is wrong with this approah?

Where's
wally ?

Irina/Lisbon/Portugal

March 13th, 2002, 11:00 PM

tron

SwollenMember

Join Date: Jun 2000

Location: the master control

Posts: 264

Time spent in forums: 13 h 14 m 57 sec
Reputation Power: 13

you need to have more try blocks, and you tried to execute the query when it should be in a try block. i would use a ResultSet interface to get the results of your statement as well...might as well use the java.sql package

plus there are a few other things that are wrong. anyway, this should clear up your troubles. also, i would suggest moving the connection attempt to a constructor somewhere. keep the java questions coming...

try{

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

Connection databaseConnection = DriverManager.getConnection("jdbc:mysql://172.16.4.39:3306/ssntvjp", "root", "");
}
catch(ClassNotFoundException cnfex){
System.err.println("Failed to load JDBC/ODBC driver.");
cnfex.printStackTrace();
System.exit(1);
}
catch(SQLException sqlex){
System.err.println("Unable to connect!");
sqlex.printStackTrace();
}
try{
String sqlString = "SELECT * FROM Descriptor D WHERE D.SubDescriptor IS NULL";
ResultSet yourResults;

Statement stmt = databaseConnection.createStatement();
yourResults = stmt.executeQuery(sqlString);
}
catch(SQLException e){
throw(e);
}
//something should be returned here