Java MySQL Database – JComboBox – INSERT SELECT UPDATE DELETE Full

Oclemy May 5, 2019 1893

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This is an Java MySQL example.

Its a simple CRUD app.We shall save items to MySQL,retrieve,update and delete.We shall be using JTextfields,JButtons and JComboBox.We used netbeans in this tutorial.

What we do :

Connect to MySQL using JDBC.
User types data into JTextField and clicks save button.
We then save this data into MySQL.
We retrieve after saving and bind our data to jcombobox.
As user enters data he can see the changes he’s made.
User can select an item from combobox.
It gets set to the corresponding jtextfield.
He can change and click update to update.
Or he can delete and it gets deleted from MySQL database.

===

SECTION 1 : Our Database Class

Database CRUD class

Main Responsibility : Perform all CRUD operations.

INSERTS/SAVES data to MySQL database.
SELECTS/RETRIEVES data to MySQL.
UPDATES/EDITS data.
DELETES data.

package ComboDataBase;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.swing.DefaultComboBoxModel;

public class DBClass {

    String conString = "jdbc:mysql://localhost:3306/playersdb";
    String username = "root";
    String password = "";

    //INSERT INTO DB
    public Boolean add(String name) {
        //SQL STMT
        String sql = "INSERT INTO playerstb(Name) VALUES('" + name + "')";

        try {
            //CONNECTION"
            Connection con = DriverManager.getConnection(conString, username, password);

            //STATEMENT
            Statement s=con.prepareStatement(sql);

            //EXECUTE
            s.execute(sql);

            return true;

        } catch (SQLException ex) {
            ex.printStackTrace();
             return false;
        }

    }

    //RETRIEVE DATA
    public DefaultComboBoxModel retrieve()
    {
        DefaultComboBoxModel dm=new DefaultComboBoxModel();

        //SQL
        String sql="SELECT Name FROM playerstb";

        try
        {
            Connection con=DriverManager.getConnection(conString, username, password);

            //STATEMENT
            Statement s=con.prepareStatement(sql);
            ResultSet rs=s.executeQuery(sql);

            //LOOP THRU GETTING ALL VALUES
            while(rs.next())
            {
                //GET VALUES
                String name=rs.getString(1);

                dm.addElement(name);
            }

            return dm;

        }catch (SQLException ex) {
            ex.printStackTrace();
             return null;
        }

    }

    //UPDATE DATA
    public Boolean update(String id,String value)
    {
        String sql="UPDATE playerstb SET Name ='" + value + "' WHERE Name='" + id + "'";

        try
        {
            //GET COONECTION
            Connection con=DriverManager.getConnection(conString, username, password);

            //STATEMENT
            Statement s=con.prepareStatement(sql);

            //EXECUTE
            s.execute(sql);

            return true;

        }catch (SQLException ex) {
            ex.printStackTrace();
             return false;
        }

    }

    //DELETE
    public Boolean delete(String id)
    {
        String sql="DELETE FROM playerstb WHERE Name ='"+id+"'";

        try
        {
            //GET COONECTION
            Connection con=DriverManager.getConnection(conString, username, password);

             //STATEMENT
            Statement s=con.prepareStatement(sql);

            //EXECUTE
            s.execute(sql);

            return true;

        }catch (SQLException ex) {
            ex.printStackTrace();
             return false;
        }

    }
}

SECTION 2 : Our GUI Class

GUI and Main class

Main Responsibility : STARTS OUR APPLICATION

Is our main class.
Derives from JFrame.
Handles all GUI interactions such as input of data.
Instantiates Database class and invokes its database manipulation methods.

package ComboDataBase;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JOptionPane;
import javax.swing.UIManager;

public class GUI_Class extends javax.swing.JFrame {

  String id="";

    public GUI_Class() {
        initComponents();
    }

   private void retrieve()
   {
       DefaultComboBoxModel dm=new DBClass().retrieve();
       jComboBox1.setModel(dm);
   }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jLabel2 = new javax.swing.JLabel();
        jPanel1 = new javax.swing.JPanel();
        jComboBox1 = new javax.swing.JComboBox();
        jLabel1 = new javax.swing.JLabel();
        nameTxt = new javax.swing.JTextField();
        addBtn = new javax.swing.JButton();
        retrieveBtn = new javax.swing.JButton();
        updateBtn = new javax.swing.JButton();
        deleteBtn = new javax.swing.JButton();
        clearBtn = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel2.setText("ProgrammingWizards Channel");

        jPanel1.setBackground(new java.awt.Color(45, 155, 193));

        jComboBox1.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                jComboBox1ItemStateChanged(evt);
            }
        });

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(41, 41, 41)
                .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 129, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(66, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(58, 58, 58)
                .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(64, Short.MAX_VALUE))
        );

        jLabel1.setText("Name");

        addBtn.setText("Add");
        addBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                addBtnActionPerformed(evt);
            }
        });

        retrieveBtn.setText("Retrieve");
        retrieveBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                retrieveBtnActionPerformed(evt);
            }
        });

        updateBtn.setText("Update");
        updateBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                updateBtnActionPerformed(evt);
            }
        });

        deleteBtn.setText("Delete");
        deleteBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                deleteBtnActionPerformed(evt);
            }
        });

        clearBtn.setText("Clear");
        clearBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                clearBtnActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(18, 18, 18)
                        .addComponent(jLabel1)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(nameTxt))
                    .addGroup(layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(layout.createSequentialGroup()
                                .addGap(8, 8, 8)
                                .addComponent(addBtn)
                                .addGap(18, 18, 18)
                                .addComponent(retrieveBtn))
                            .addGroup(layout.createSequentialGroup()
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addComponent(updateBtn)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                .addComponent(deleteBtn)))
                        .addGap(0, 0, Short.MAX_VALUE)))
                .addContainerGap())
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(clearBtn)
                .addGap(65, 65, 65))
            .addGroup(layout.createSequentialGroup()
                .addGap(115, 115, 115)
                .addComponent(jLabel2)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(31, 31, 31)
                .addComponent(jLabel2)
                .addGap(51, 51, 51)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGroup(layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel1)
                            .addComponent(nameTxt, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGap(58, 58, 58)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(addBtn)
                            .addComponent(retrieveBtn))
                        .addGap(28, 28, 28)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(updateBtn)
                            .addComponent(deleteBtn))))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(clearBtn)
                .addContainerGap(18, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    private void jComboBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
       id=jComboBox1.getSelectedItem().toString();
       nameTxt.setText(id);
    }

    private void addBtnActionPerformed(java.awt.event.ActionEvent evt) {
        if(new DBClass().add(nameTxt.getText()))
        {
            JOptionPane.showMessageDialog(null, "Successfully Inserted");
            retrieve();;

             //SELECT ADDED ITEM
            jComboBox1.setSelectedItem(nameTxt.getText());
            //CLEAR TXT
            nameTxt.setText("");
        }else
        {
            JOptionPane.showMessageDialog(null, "Not Inserted");
        }
    }

    private void retrieveBtnActionPerformed(java.awt.event.ActionEvent evt) {
      retrieve();
    }

    private void updateBtnActionPerformed(java.awt.event.ActionEvent evt) {
       if(new DBClass().update(id,nameTxt.getText()))
        {
            JOptionPane.showMessageDialog(null, "Successfully Updated");
            retrieve();;

             //SELECT ADDED ITEM
            jComboBox1.setSelectedItem(nameTxt.getText());
            //CLEAR TXT
            nameTxt.setText("");
        }else
        {
            JOptionPane.showMessageDialog(null, "Not Updated");
        }
    }

    private void deleteBtnActionPerformed(java.awt.event.ActionEvent evt) {
         if(new DBClass().delete(id))
        {
            JOptionPane.showMessageDialog(null, "Successfully Deleted");
            retrieve();;

            //CLEAR TXT
            nameTxt.setText("");
        }else
        {
            JOptionPane.showMessageDialog(null, "Not Deleted");
        }
    }

    private void clearBtnActionPerformed(java.awt.event.ActionEvent evt) {
        jComboBox1.setModel(new DefaultComboBoxModel());
    }

    public static void main(String args[]) {

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
//                 try {
//                    // select Look and Feel
//                    UIManager.setLookAndFeel("com.jtattoo.plaf.smart.SmartLookAndFeel");
//            // start application
//
//                } catch (Exception ex) {
//                    ex.printStackTrace();
//                }
                new GUI_Class().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify
    private javax.swing.JButton addBtn;
    private javax.swing.JButton clearBtn;
    private javax.swing.JButton deleteBtn;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JTextField nameTxt;
    private javax.swing.JButton retrieveBtn;
    private javax.swing.JButton updateBtn;
    // End of variables declaration
}

LAST SECTION

Lets share more tips in OUR FB PAGE.
To see the XML we were parsing and the website itself please have look at the tutorial at our youtbe channel : ProgramminWizards.
You’ll also find the demo for this example and step by step explanations.

Tags:

Java MySQL

Oclemy

Around 5 years ago, my life changed when I got enrolled in Software Engineering at the undergraduate level rather than Law. Since then I have fallen in love with coding. When not coding am probably meditating or going for long Savanna walks. Subscribe to my YouTube Channel below.

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What we do :

SECTION 1 : Our Database Class

Database CRUD class

SECTION 2 : Our GUI Class

GUI and Main class

LAST SECTION

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