net.ucanaccess.jdbc.UcanaccessSQLException:尝试分配给不可更新的列

Question

           try{
            //taking input from user about how much balance
            Scanner input = new Scanner(System.in);
            Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
            String url = "jdbc:ucanaccess://c://Bibek//Atmcard.accdb";
            System.out.print("nConnecting to database...");
            con = DriverManager.getConnection(url);
            st = con.createStatement();
            System.out.println("n Enter balance you want to withdraw:n");

            balance = Double.parseDouble(input.nextLine());
            String sql = "select AccountBalance From Atm";
            result = st.executeQuery(sql);
                while(result.next()){
                    //assigning balanceFromDb to deduct and update in database
                    Double balanceFromDb = result.getDouble("AccountBalance");
                    balanceFromDb=balanceFromDb-balance;
                    result.updateDouble("AccountBalance", balanceFromDb);
                    result.updateRow();
                }

    }catch(Exception ex){
            System.err.println(ex.toString());
    }

输出：正在连接到数据库... 输入您要提取的余额：

20

net.ucanaccess.jdbc.UcanaccessSQLException：尝试分配给不可更新的列

Answer 1

检查访问数据库中的 Atm 对象，并确保它是一个表而不是查询。还要检查帐户余额的数据类型，并确保它是可编辑字段。如果它是自动递增或计算的，您将无法更新它。

编辑：看起来您必须将其声明为可更新的光标。这是来自 ucanacces 关于源代码锻造 http://ucanaccess.sourceforge.net/site.html 的示例 使用可更新的结果集

PreparedStatement ps =     super.ucanaccess.prepareStatement( "SELECT *  FROM T1", ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_UPDATABLE, ResultSet.CLOSE_CURSORS_AT_COMMIT);
rs = ps.executeQuery();
rs.next(); 
rs.updateString(2, "show must go off"); 
rs.updateRow();