一个字段中有多个值（外键？） [英] Multiple values in one field (foreign keys?)

问题描述

我正在尝试订购系统，您可以在一个订单中放置许多产品。我对这一点知之甚少，现在我正在

有3个表格，Product表格，Order表格和订购产品表。
我真的不知道这是否正确，因为我是初学者，尤其是外键。

我想要达到的是您可以订购许多产品和把这个产品放到一个OrderID中，如下图所示。

这是我唯一的代码。对不起，但我真的迷失在这。

  public Form1（）
 {
 InitializeComponent（）; 
 fillCart（）; 
 
 
 $ b $ private void fillCart（）
 {
 dgvCart.ColumnCount = 3; 
 dgvCart.Columns [0] .Name =ProductID; 
 dgvCart.Columns [1] .Name =ProductName; 
 dgvCart.Columns [2] .Name =Quantity; 
 
 $ b $ private void dataGridView1_CellClick（object sender，DataGridViewCellEventArgs e）
 {
 // dgvproducts 
} 
 
 private void Form1_Load（object sender，EventArgs e）
 {
 crud.FillDataGrid（Select * from Products，ref dgvProducts）; 
 crud.FillDataGrid（Select * from Orders，ref dgvOrder）; 
 crud.FillDataGrid（Select * from Orderproducts，ref dgvOrderview）; 
 lbldate.Text = DateTime.Now.ToShortDateString（）; 
 
 $ b $ private void button2_Click（object sender，EventArgs e）
 {
 //按钮添加到购物车
 addData（dgvProducts.CurrentRow.Cells [ 0] .Value.ToString（），dgvProducts.CurrentRow.Cells [1] .Value.ToString（），txtqty.Text）; 
 
 
 private void addData（string p1，string p2，string p3）
 {
 String [] row = {p1，p2，p3}; 
 dgvCart.Rows.Add（row）; 
 
 $ b $ private void button1_Click（object sender，EventArgs e）
 {
 //按钮插入
 
} 
  

非常感谢您，我希望有人可以帮我解决我的问题。

$ b $使用SQL Server 2008填充datagridview的方法：

  public crud（）
 {
 cnString =Data Source = DESKTOP-MQKIBSK\\\SQLEXPRESS; Initial Catalog = MARISCHELLdatabase; Integrated Security = True; 
 cn = new SqlConnection（cnString）; 
 
 
 
 $ b public void FillDataGrid（string sql，ref ns1.BunifuCustomDataGrid dg）
 {
 try 
 {
 DataSet ds = new DataSet（）; 
 cn.Open（）; 
 cmd = new SqlCommand（sql，cn）; 
 adptr = new SqlDataAdapter（cmd）; 
 adptr.Fill（ds）; 
 dg.DataSource =; 
 dg.DataSource = ds.Tables [0]; 
 
 
 $ b catch（Exception e）
 {
 MessageBox.Show（+ e.Message）; 
} 
 cn.Close（）; 
 
  

解决方案

Linq 2 SQL数据类对我来说：

使用它的代码：

  //我在dataGridView中有2列，Id第一个数量第二个
 //我添加了3个项目用于测试
 List< Tuple< int， INT>> cart = new List< Tuple< int，int>>（）; 
 foreach（DataGridViewRow row dataGridView1.Rows）
 {
 if（row.Cells [0] .Value！= null&&& row.Cells [1] .Value！= null ）
 {
 cart.Add（new Tuple< int，int>（Convert.ToInt32（row.Cells [0] .Value.ToString（）），Convert.ToInt32（row.Cells [1] .Value.ToString（））））; 
 //现在每个列表项都会有.Item1（productId）和.Item2（amount）
} 
} 
 using（DataClasses1DataContext dataContext = new DataClasses1DataContext（））
 {
 //你在dataContext中添加的表可以通过名称
来访问。Order order = new Order（）; 
 dataContext.Orders.InsertOnSubmit（order）; 
 dataContext.SubmitChanges（）; //提交一次，所以我们得到一个orderId 
 foreach（元组中的元组< int，int>产品）
 {
 OrderProduct orderProduct = new OrderProduct（）; 
 orderProduct.OrderId = order.OrderID; 
 orderProduct.ProductId = product.Item1; 
 orderProduct.Amount = product.Item2; 
 dataContext.OrderProducts.InsertOnSubmit（orderProduct）; 
} 
 dataContext.SubmitChanges（）; 
} 
  

I am trying to do an Ordering System where you can put many Products in one order. I have very little knowledge about this and this is where i am now

There are 3 tables, Product table,Order table and the Order-products table. I really don't know if this is right as i am beginner especially on foreign keys.

What I want to achieve is you can order many products and put that products into one "OrderID" like this example in pic below.

This are my only codes. Sorry but i am really lost at this.

    public Form1()
    {
        InitializeComponent();
        fillCart();
    }


    private void fillCart()
    {
        dgvCart.ColumnCount = 3;
        dgvCart.Columns[0].Name = "ProductID";
        dgvCart.Columns[1].Name = "ProductName";    
        dgvCart.Columns[2].Name = "Quantity";
    }

    private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
    {
        //dgvproducts
    }

    private void Form1_Load(object sender, EventArgs e)
    {
       crud.FillDataGrid("Select * from Products", ref dgvProducts);
       crud.FillDataGrid("Select * from Orders", ref dgvOrder);
       crud.FillDataGrid("Select * from Orderproducts", ref dgvOrderview);
       lbldate.Text = DateTime.Now.ToShortDateString();
    }

    private void button2_Click(object sender, EventArgs e)
    {
        //button add to cart
        addData(dgvProducts.CurrentRow.Cells[0].Value.ToString(), dgvProducts.CurrentRow.Cells[1].Value.ToString(), txtqty.Text);
    }

    private void addData(string p1, string p2, string p3)
    {
        String[] row = { p1, p2, p3 };
        dgvCart.Rows.Add(row);
    }

    private void button1_Click(object sender, EventArgs e)
    {
        //button insert

    }

Thank you very much and i hope someone can help me with my problem.

Method use for filling datagridview from SQLserver 2008:

      public crud()
    {
        cnString = "Data Source=DESKTOP-MQKIBSK\\SQLEXPRESS;Initial Catalog=MARISCHELLdatabase;Integrated Security=True";
        cn = new SqlConnection(cnString);
    }



    public void FillDataGrid(string sql, ref ns1.BunifuCustomDataGrid dg)
    {
        try
        {
            DataSet ds = new DataSet();
            cn.Open();
            cmd = new SqlCommand(sql, cn);
            adptr = new SqlDataAdapter(cmd);
            adptr.Fill(ds);
            dg.DataSource = "";
            dg.DataSource = ds.Tables[0];


        }
        catch (Exception e)
        {
            MessageBox.Show("" + e.Message);
        }
        cn.Close();
    }

解决方案

How Linq 2 SQL dataclasses look for me:

The code that goes with it:

//I have 2 columns in my dataGridView, Id 1st amount 2nd
//I added 3 items for testing
List<Tuple<int, int>> cart = new List<Tuple<int,int>>();
foreach (DataGridViewRow row in dataGridView1.Rows)
{
    if (row.Cells[0].Value != null && row.Cells[1].Value != null)
    { 
        cart.Add(new Tuple<int, int>(Convert.ToInt32(row.Cells[0].Value.ToString()),Convert.ToInt32(row.Cells[1].Value.ToString())));
                //Now each list item will have .Item1 (productId) and .Item2 (amount)
    }
}
using (DataClasses1DataContext dataContext = new DataClasses1DataContext())
{
    //The tables you add in the dataContext are accessible by name
    Order order = new Order();
    dataContext.Orders.InsertOnSubmit(order);
    dataContext.SubmitChanges(); // Submit once so we get an orderId
    foreach (Tuple<int, int> product in cart)
    {
        OrderProduct orderProduct = new OrderProduct();
        orderProduct.OrderId = order.OrderID;
        orderProduct.ProductId = product.Item1;
        orderProduct.Amount = product.Item2;
        dataContext.OrderProducts.InsertOnSubmit(orderProduct);
    }
    dataContext.SubmitChanges();
}

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