无法通过Java在Netbeans上执行SQL查询

Question

I'm trying to update my SQL database using JBDC. But for some reason the query doesn't seem to be executing. I'm using a Jframe GUI for my login screen and menu.

What I'm trying to do is to get the account number entered in the login screen and take the amount entered by the user and minus that by the current balance and then pass the account number and the renaming amount to the database and update the account balance.

This is the declaration part of some values:

public class MainMenu extends javax.swing.JFrame
{
    private Login log = new Login();

    private Account acc = null;
    private String accnum = log.getacctfld();

    Connection con = new DBConnection().connect();    
}

This is the code for the withdraw button:

private void withdrawActionPerformed(java.awt.event.ActionEvent evt)                                         
{                                             
    String input = amountentered.getText();

    if ("".equals(input))
    {
        message.setText("Enter amount to perform operation");
        return;
    }

    Double amt = Double.parseDouble(input);

    if (amt > acc.getAmount() || amt <= 0.0) 
    {
        message.setText("INVALID AMOUNT. PLEASE TRY AGAIN.");

        return;
    }

    double bal = acc.getAmount() - amt;

    String command = "UPDATE user_atm SET balance =? WHERE accno =?";

    try
    {     
        PreparedStatement ps = con.prepareStatement(command);

        ps.setDouble(1, bal);
        ps.setString(2, accnum);

        ps.executeQuery(); // I think the query isn't executing
        ps.executeUpdate();

    }
    catch(Exception e)
    {

    }

    acc.setAmount(bal);

    balance.setText(bal + "");
    amountentered.setText("");

} 

UPDATE:

The accnum wasn't being initialized. I was trying to pass the value from the JTextField from my Login screen. But it wasn't working. So I passed the account number to the setter and then assigned accnum to the getter and now it's working.

I also removed ps.executeQuery();

Answer 1

You must use executeUpdate() instead of executeQuery()
From what I understood you want to update data in the db isn't this case?
executeQuery() is used with SELECT statements to fetch rows and not udate.
So remove ps.executeQuery();