数据库更新产品的数量，如果java中的代码是jtable

Question

我已经为商店创建了一个pos系统。销售产品时，所有属性都存储在jtable中，然后插入到数据库中。如果产品多次出现，我想更新/增加产品数量

我的代码如下。但它并不奏效。它正在更新同一产品的数量，但如果出现不同的产品，则不会在表中添加超过1行

 DefaultTableModel model = (DefaultTableModel) sale_table.getModel();
                int numofRows = sale_table.getRowCount();

                if (numofRows == 0) {

                    Vector v = new Vector();
                    v.add(s_pname.getText());
                    v.add(s_bcode.getText());
                    v.add(s_mar_price.getText());
                    v.add(our_price.getText());
                    v.add(s_qty.getValue().toString());
                    v.add(s_t_discount.getText());
                    v.add(s_t_price.getText());
                    v.add(t_profit.getText());
                    model.addRow(v);

                    sale_cart_tot();    
                    store_profit();

                    // Calculate the Balance amount
                    Double paid = 0.0;
                    Double tot = Double.valueOf(cart_total.getText());
                    Double due;

                    due = paid - tot;

                    cart_bal.setText(String.valueOf(due));


                    s_bcode.setText("");
                    s_pname.setText("");
                    s_mar_price.setText("");
                    s_t_price.setText("");
                    our_price.setText("");
                    s_t_discount.setText("");
                    s_bcode.requestFocus();

                    s_qty.setValue(0b1);

                }
                
                else if (numofRows != 0) {
                    for (int i = 0; i <= numofRows; i++) {
                        String tb_bcode = sale_table.getValueAt(i, 1).toString();
                        while (bcode.equals(tb_bcode)) {

                            int tb_qty = Integer.parseInt(sale_table.getValueAt(i, 4).toString());
                            double tb_dis = Double.valueOf(s_t_discount.getText());
                            double tb_tprice = Double.valueOf(s_t_price.getText());
                            double tb_profit = Double.valueOf(u_profit.getText());

                            int update_qty = tb_qty + 1;
                            double update_dis = update_qty * tb_dis;
                            double update_tprice = update_qty * tb_tprice;
                            double update_profit = update_qty * tb_profit;

                            sale_table.setValueAt(update_qty, i, 4);
                            sale_table.setValueAt(update_dis, i, 5);
                            sale_table.setValueAt(update_tprice, i, 6);
                            sale_table.setValueAt(update_profit, i, 7);

                            sale_cart_tot();    

                           
                            store_profit();

                            
                            Double paid = 0.0;
                            Double tot = Double.valueOf(cart_total.getText());
                            Double due;

                            due = paid - tot;

                            cart_bal.setText(String.valueOf(due));

                            s_bcode.setText("");
                            s_pname.setText("");
                            s_mar_price.setText("");
                            s_t_price.setText("");
                            our_price.setText("");
                            s_t_discount.setText("");
                            s_bcode.requestFocus();

                            s_qty.setValue(0b1);

                        }

                    }

                } else if(numofRows != 0){
                
                    Vector v = new Vector();
                    v.add(s_pname.getText());
                    v.add(s_bcode.getText());
                    v.add(s_mar_price.getText());
                    v.add(our_price.getText());
                    v.add(s_qty.getValue().toString());
                    v.add(s_t_discount.getText());
                    v.add(s_t_price.getText());
                    v.add(t_profit.getText());
                    model.addRow(v);

                    sale_cart_tot();  


                    store_profit();


                    Double paid = 0.0;
                    Double tot = Double.valueOf(cart_total.getText());
                    Double due;

                    due = paid - tot;

                    cart_bal.setText(String.valueOf(due));


                    s_bcode.setText("");
                    s_pname.setText("");
                    s_mar_price.setText("");
                    s_t_price.setText("");
                    our_price.setText("");
                    s_t_discount.setText("");
                    s_bcode.requestFocus();

                    s_qty.setValue(0b1);
                    JOptionPane.showMessageDialog(null, "Different");
  
                }

谁能解决我的问题