Can't get the table display my results
OK After some good hours of debugging i am able to display my results on JTable for my queries. But i got another problem now. When i select Query2 from my JComboBox and click on execute button nothing happens, same thing for query3 and 4. The only thing which works is QUERY1 why? what am i doing wrong?
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
import java.awt.event.ActionEvent;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Vector;
publicclass DatabaseProgrammingextends JFrameimplements ActionListener{
staticfinal String JDBC_DRIVER ="com.mysql.jdbc.Driver";
staticfinal String DATABASE_URL ="jdbc:mysql://localhost/employees";
staticfinal String USERNAME ="jhtp6";
staticfinal String PASSWORD ="jhtp6";
privatestaticfinal String QUERY1 ="SELECT * FROM employees WHERE DEPARTMENTNAME = 'SALES'";
privatestaticfinal String QUERY2 ="SELECT * FROM hourlyEmployees WHERE hours >= '30'";
privatestaticfinal String QUERY3 ="SELECT * FROM commissionEmployees ORDER BY commissionRate DESC";
private String names[] ={"QUERY1","QUERY2","QUERY3","QUERY4"};
private Connection connection;
private ResultSet resultSet;
private Statement statement;
private ResultSetMetaData metaData;
private JTable resultTable;
private JComboBox queryBox;
private JButton button;
privateint number;
privateboolean connectedDatabase =false;
private DefaultTableModel dtm;
publicstaticvoid main(String[] args){
DatabaseProgramming frame =new DatabaseProgramming();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public DatabaseProgramming(){
super("Testing Database");
setLayout(new FlowLayout());
//dtm = new DefaultTableModel(getColumnName(number),0);
//statement = connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
// ResultSet.CONCUR_READ_ONLY);
queryBox =new JComboBox(names);
queryBox.setEditable(false);
//queryBox.addActionListener(this);
button =new JButton("EXECUTE");
resultTable =new JTable();
button.addActionListener(this);
add(queryBox);
add(button);
add(resultTable);
//add(result);
setSize(400,400);
}
publicvoid actionPerformed(ActionEvent e){
String selection = (String)queryBox.getSelectedItem();
if(selection.equals(names[0]))
validateQuery(QUERY1);
if(selection.equals(QUERY2))
validateQuery(QUERY2);
if(selection.equals(QUERY3))
validateQuery(QUERY3);
}
publicvoid validateQuery(String query){
try{
Class.forName(JDBC_DRIVER);
connection = DriverManager.getConnection(DATABASE_URL, USERNAME, PASSWORD);
System.out.println("Yay Database Connected");
Vector col =new Vector();
Vector data =new Vector();
statement = connection.createStatement();
resultSet = statement.executeQuery(query);
metaData = resultSet.getMetaData();
number = metaData.getColumnCount();
for(int i=1; i<=number; i++)
col.addElement(metaData.getColumnName(i));
while(resultSet.next()){
Vector row =new Vector();
for(int i=1; i<=number; i++)
row.addElement(resultSet.getObject(i));
data.addElement(row);
}
resultTable.setModel(new DefaultTableModel(data,col));
resultTable.revalidate();
}
catch ( SQLException sqlException )
{
sqlException.printStackTrace();
System.exit( 1 );
}
catch(ClassNotFoundException e){
e.printStackTrace();
}
finally
{
try
{
statement.close();
connection.close();
}
catch ( SQLException sqlException )
{
JOptionPane.showMessageDialog( null,
sqlException.getMessage(),"Database error",
JOptionPane.ERROR_MESSAGE );
System.exit( 1 );
}
}
}
}
