java-jTable数据库重复值

Question

I am trying to populate a java database with car brands, models, and if they are available but I have a big issue. When I enter multiple cars to the table, the new car prints to the table, but previous cars I have entered also reprint [Issue.png][1]. So first I entered Ferrari Enzo, then I entered Tesla S but Ferrari Enzo is repeating.

I know the issue is not with adding the cars to the database because if I look in the database it only shows the two I entered [DatabasePic.png][2]. I know my problem is with how I am entering my cars into the JTable. My methods are below..

ButtonClickEvent:

private void refreshbtnMouseClicked(java.awt.event.MouseEvent evt) {                                        
    try {
        String Brand = brandlbl.getText();
        String Model = modellbl.getText();
        Boolean Available = false;
        switch (availabilitybox.getSelectedItem().toString()) {
            case "True":
                Available = true;
                break;
            case "False":
                Available = false;
                break;
        }
        InsertApp nw = new InsertApp();
        nw.insert(Brand, Model, Available);
        nw.refreshDatabase(jTable1);
    } catch (SQLException ex) {
        Logger.getLogger(Window.class.getName()).log(Level.SEVERE, null, ex);
    }
}

Insert Method:

public void insert(String brand, String model, Boolean available) {
    String sql = "INSERT INTO CARDATA(brand,model,available) VALUES(?,?,?)";

    try (Connection conn = this.connect();
            PreparedStatement pstmt = conn.prepareStatement(sql)) {

        pstmt.setString(1, brand);
        pstmt.setString(2, model);
        pstmt.setBoolean(3, available);

        pstmt.executeUpdate();
    } catch (SQLException e) {

        System.out.println(e.getMessage());
    }

}

Refreshing my database:

public void refreshDatabase(JTable table) throws SQLException {
    Connection con = connect();
    String SQL = "SELECT * FROM CARDATA";
    Statement stmt = con.createStatement();
    ResultSet rs = stmt.executeQuery(SQL);
    int col = rs.getMetaData().getColumnCount();
    System.out.println(col);
    while (rs.next()) {
        Object[] rows = new Object[col];
        for (int i = 1; i <= col; i++) {
            rows[i - 1] = rs.getObject(i);
        }
        ((DefaultTableModel) table.getModel()).insertRow(rs.getRow() - 1, rows);
    }
    con.close();
    rs.close();
    stmt.close();
}

Answer 1

When I enter multiple cars to the table, the new car prints to the table, but previous cars I have entered also reprint

You need to clear the data in the TableModel before you start adding data back into it.

The basic code should be something like:

DefaultTableModel model = (DefaultTableModel)table.getModel();
model.setRowCount(0);

while (rs.next()) 
{
    ...

    model.addRow(...);
}

Or instead of retrieving all the data from the database every time you do an insert, just add the data to the table at the same time:

pstmt.executeUpdate();
model.addRow(...);