小编use*_*418的帖子

每当我尝试将数据输入到我的tblorder中时,我会在"字段列表"中收到错误消息#1054 - 未知列'FK_Customer_ID'.我试图破坏我的代码,并且在这样做时我发现错误是针对FK_Customer_ID和OrderQuantity重复的,而FK_DVD_ID则需要单个数据条目.我已经尝试删除表并重新创建它,我已经删除了数据库并重新创建它但没有任何作用.据我所知,我的代码与我的拼写一致是正确的,所以我真的卡住了.

我的tblorder是 -

CREATE TABLE tblorder
(   
 Order_ID INT AUTO_INCREMENT NOT NULL,  
 FK_Customer_ID INT NOT NULL,   
 FK_DVD_ID INT NOT NULL,    
 OrderDate DATETIME NOT NULL DEFAULT NOW(),
 OrderQantity INT NOT NULL, 
 PRIMARY KEY (Order_ID),    
 FOREIGN KEY (FK_Customer_ID) REFERENCES tblcustomer (Customer_ID), 
 FOREIGN KEY (FK_DVD_ID) REFERENCES tbldvd (PK_ID)
);

我试图提供的数据是 -

INSERT INTO tblorder
 (FK_Customer_ID, FK_DVD_ID, OrderQuantity)
VALUES 
 (1, 3, 2),
 (1, 5, 1),
 (1, 10, 4), 
 (1, 15, 3),
 (2, 5, 4),
 (2, 17, 3),
 (3, 15, 1),
 (3, 16, …

我想让我的菜单重复,所以在选择并执行选项1之后,它将返回菜单并要求选择另一个选项

class Program
{
    static void Main(string[] args)
    {

        FootballTeams MyCode = new FootballTeams();

        MyCode.ListInit();
        MyCode.DisplayMenu();
        MyCode.AddTeams();
        Console.ReadLine();

        MyCode.ListInit();
        MyCode.DisplayMenu();
        MyCode.DisplayTeams();
        Console.ReadLine();

        MyCode.ListInit();
        MyCode.DisplayMenu();
        MyCode.Delete();
        Console.ReadLine();

        MyCode.ListInit();
        MyCode.DisplayMenu();
        MyCode.TeamSearch();
        Console.ReadLine();
    }
}

以下是取出内容的方法:

class FootballTeams
{


    public FootballTeams(){ }

    List<string> teams;
    public void ListInit()


    public void DisplayMenu()
   {   
    Console.WriteLine("Football Manager");
    Console.WriteLine();
    Console.WriteLine("1. Add a Football team");
    Console.WriteLine("2. List the Football teams");
    Console.WriteLine("3. Search for a Football team");
    Console.WriteLine("4. Delete a team");
    Console.ReadLine();
    }



    public void AddTeams()
    {
      Console.WriteLine("Enter a team …

我有一个网页,用户输入他们当前的用户名和密码.如果它们与数据库中的用户匹配,则密码将更改为新密码.

如果没有错误并且密码已更改,则用户将被重定向到初始登录页面.如果出现错误,则会显示错误消息.

但是,目前密码没有改变,并且当应该有错误时,即当密码没有改变时,它只是将用户重定向到登录页面.

我的代码:

public static MySqlConnection CreateConnection()
    {

        String connectionString = "SERVER=127.0.0.1; DATABASE='dbnumericalmethods'; UID='root'; PASSWORD=''";
        MySqlConnection SqlConnection = new MySqlConnection(connectionString);
        return SqlConnection;
    }

    protected void btnChange_Click(object sender, EventArgs e)
    {
        MySqlConnection SqlConnection = CreateConnection();
        string OldPassword;
        string NewPassword;
        string Username;
        string ConfirmPassword;
        Username = txtUsername2.Text;  
        OldPassword = txtOldPassword.Text;
        NewPassword = txtNewPassword.Text;
        ConfirmPassword = txtConfirmPassword.Text;
        string SqlString = "update tblLogin set Identification='" + NewPassword + "' WHERE [Identification]='" + OldPassword + "' AND Username='" + Username + "'";
        SqlConnection.Open();
        MySqlCommand …