Question

我有2张桌子： salon_stock 类

salon_stock表有一个类别表的fk列cat_id

分类表有2列cat_id＆amp;标题

在下面的代码中，我试图插入属于类别名称的cat_id 从JComboBox中检索以及salon_stock表的数据

    private void AddStock() throws SQLException,NullPointerException {

int catID = 0; 

String cat=cat_list.getSelectedItem().toString();

            if (cat.equals("Select a Category")) {
                 ResultSet rs = con.createStatement().executeQuery("select * from categories where title=' Default'");

            if(rs.next()){
                catID=rs.getInt("cat_id");
            }
            else{
                throw new SQLException("The 'Default' category was not found in the Categories Table");
            }

            }
            else{
          ResultSet rs = con.createStatement().executeQuery("select * from categories where title=' "+cat+"'");

            if(rs.next()){
               catID=rs.getInt("cat_id");
               }
            }

          ps1 = con.prepareStatement("insert into "+tableName+"(title,price,qty,cat_id) values( ?,?,?,?)");

          ps1.setString(1,title_field.getText());
          ps1.setInt(2,Integer.parseInt(price_field.getText()));
          ps1.setInt(3,Integer.parseInt(qty_field.getText()));
          ps1.setInt(4,catID);
          ps1.executeUpdate();
          ps1.closeOnCompletion();

    }

代码运行正常但在表中，它将'0'值插入stock_table的cat_id列。

我无法检测到错误.. 请帮帮我..

Answer 1

查询中的空格可能是错误：

"select * from categories where title=' "+cat+"'"

必须是

"select * from categories where title='"+cat+"'"

无法获取类别ID（java / sql）

1 个答案: