Question

正如标题所述，我正在使用MS Access，但遇到了一些麻烦。

老实说，我无法弄清楚如何从数据库的20个元素中随机选择5个。我一直在尝试在线找到它，所以我一直试图确保至少可以使用所有信息创建表。如果您想为我提供帮助，我将不胜感激，但我知道人们不喜欢在此类网站上发布代码。我主要只关注下一部分。

程序运行正常，并且出现抽奖成功的消息，但未在Access中创建表。我的教授似乎认为这与打开数据库时出现的记录锁定文件有关。老实说他不是最好的程序员，但是显然他比我更博学。这可能是问题还是我的代码不正确？

        Connection raffleconnection = null;
        Statement rafflestatement = null;

        ResultSet rsTickets = null;


        // Loading or registering Oracle JDBC driver class
        try {

            Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
        }
        catch(ClassNotFoundException cnfex) {

            System.out.println("Problem in loading or "
                    + "registering MS Access JDBC driver");
            cnfex.printStackTrace();
        }

        // Opening database connection
        try {

            String strDatabase = "C:\\Users\\nikol\\OneDrive\\Documents\\Fall Semester 2018\\MIS 413\\AdidasRaffle\\AdidasRaffle.accdb";
            String strURL = "jdbc:ucanaccess://" + strDatabase; 

            // Create and get connection using DriverManager class
            raffleconnection = DriverManager.getConnection(strURL); 

            // Creating JDBC Statement 
            rafflestatement = raffleconnection.createStatement();

            int intTicketNum = 0;
            int intRaffleCustID = 0;

            // Executing SQL; retrieve data into ResultSet
            rsTickets = rafflestatement.executeQuery("SELECT * FROM Tickets");

            while (rsTickets.next()) {
                intTicketNum = rsTickets.getInt("TicketID");
                intRaffleCustID = rsTickets.getInt("CustomerID");


            }


            rafflestatement.executeQuery("CREATE TABLE Winners (TicketID INT not NULL, CustomerID INT, PRIMARY KEY (TicketID))");

            rafflestatement.executeQuery("INSERT into Winners (TicketID, CustomerID) VALUES('" + intTicketNum + "','" + intRaffleCustID +"')");             

        }

        catch(SQLException sqlex){
            sqlex.printStackTrace();
            JOptionPane.showMessageDialog(null, "Database Connection Failed");
        }
        finally {
            JOptionPane.showMessageDialog(null, "Raffle Successful");
            // Closing database connection
            try {
                if(null != raffleconnection) {

                    // cleanup resources, once after processing
                    rsTickets.close();

                    rafflestatement.close();


                    // and then finally close connection
                    raffleconnection.close();
                }
            }
            catch (SQLException sqlex) {
                sqlex.printStackTrace();
            }

        }

从MS Access中的一个表中随机选择值，然后将其插入到另一个表中

0 个答案: