Java: Deleting a record from MySQL databbase

• Create a simple GUI using GridBagLayout
• Get input from the user to delete the corresponding record
• Delete a record from the database on pressing the button

We will delete a customer record from the database. User has to provide the customer account number in order to delete the customer. The program will contain a class for handling database transaction, one for creating the GUI and a driver program.

Here is the class that creates our GUI.

public class SimplePanel extends JFrame

{

JTextField accountNumber;

public SimplePanel()

{

setTitle("Delete record from Database");

accountNumber = new JTextField(10);

}

public void createAndDisplay()

{

JPanel panel = new JPanel(new GridBagLayout());

JPanel banner = new JPanel();

banner.add(new JLabel("Delete record from the database"), BorderLayout.CENTER);

banner.setBorder(BorderFactory.createLineBorder(Color.BLACK));

GridBagConstraints c = new GridBagConstraints();

c.gridx = 0;

c.gridy = 0;

c.gridwidth = 2;

panel.add(banner, c);

JLabel label = new JLabel("Customer Account Number");

c.gridx = 0;

c.gridy = 2;

c.gridwidth = 1;

panel.add(label, c);

c.gridx = 1;

c.gridy = 2;

c.gridwidth = 1;

panel.add(accountNumber, c);

JButton deleteBtn = new JButton("Delete");

deleteBtn.addActionListener(new ActionListener()

{

@Override

public void actionPerformed(ActionEvent arg0)

{

CustomerHandler handler = new CustomerHandler();

try

{

handler.deleteCustomer(Integer.valueOf(accountNumber.getText()));

}

catch (Exception e)

{

e.printStackTrace(); // handle the exception in a better way. this is just an example

}

}

});

c.gridx = 0;

c.gridy = 3;

panel.add(deleteBtn, c);

this.getContentPane().add(panel);

pack();

setVisible(true);

}

}

Here is the output window from the above program

For the DBConnection class have a look at this post. And the handler that will actually delete the record from the database

public class CustomerHandler

{

public void deleteCustomer(int customerAccouontNumer) throws Exception

{

DBConnection db = new DBConnection();

Connection conn = db.getConnection();

Statement st = null;

              // First check if the conn is null then throw an exception or handle in some other way

try

{

st = conn.createStatement();

st.execute("Delete from Customer where account_number = " + customerAccouontNumer + ";");

}

catch (Exception e1)

{

throw new Exception("Unable to delete customer!" + e1.getMessage());

}

finally

{

// close the connection and the statement

}

}

And the driver program

public class Driver

{

public static void main(String[] args)

{

javax.swing.SwingUtilities.invokeLater(new Runnable()

{

public void run()

{

SimplePanel p = new SimplePanel();

p.createAndDisplay();

}

});

}

}

Remember to do the imports.