Question

我想在多对多关系表中插入值我正在使用实体框架＆amp; LINQ。我想建立插入查询（.net Framework 4）

以下是表格

菜单 - menu_id， MENU_NAME， menu_desc

Cater - cater_id， cater_name， enable_ind

关系表 Menu_Cater - menu_id， cater_id

我试过几个案例似乎不起作用，如果有一种简单的方法来实现这个插入＆amp;删除

Answer 1

假设您拥有Menu和Cater个对象（或者从下拉列表中删除），只需：

创建Menu_Cater记录
将其设置为在提交时插入
提交更改

以下展示：

<强> VB.NET

Dim menu As Menu = GetSelectedMenu() ' However you get the Menu record
Dim cater As Cater = GetSelectedCater() ' However you get the Cater record

Dim relationship = New Menu_Cater()
' EITHER:
relationship.menu_id = menu.menu_id
relationship.cater_id = cater.cater_id
' OR:
' relationship.menu = menu
' relationship.cater = cater

Using db = new MyDataContext
    db.Menu_Cater.InsertOnSubmit( relationship )
    db.SubmitChanges()
End Using

<强> C＃

Menu menu = GetSelectedMenu(); // However you get the Menu record
Cater cater = GetSelectedCater(); // However you get the Cater record

Menu_Cater relationship = new Menu_Cater();
// EITHER:
relationship.menu_id = menu.menu_id;
relationship.cater_id = cater.cater_id;
// OR:
// relationship.menu = menu
// relationship.cater = cater

using (db = new MyDataContext()) {
    db.Menu_Cater.InsertOnSubmit(relationship);
    db.SubmitChanges();
}

可能需要对变量/数据库字段名称进行小的更改。可能db.Save()而不是db.SubmitChanges()，具体取决于数据上下文的类型。

Answer 2

我不知道，如果你现在需要它，但我会展示如何做到这一点。如果我理解得对，你的意思就是这样。

public ActionResult Create(Cater cater, int menuId)
{
    //Find menu with our menu_id
    Menu menu = db.Menus.Where(m => m.menu_id == menuId).FirstOrDefault();

    //Add cater for this Menu
    menu.Cater.Add(cater);
    db.SaveChanges();

    return somethere...
}

public ActionResult Remove(int caterId, int menuId)
{
 //Choose menu, from him we will delete cater which we need 
 Menu menu = db.Menus.Where(m => m.menu_id == menuId).FirstOrDefault();

 //Find cater which we want delete from this Menu
 Cater cater = menu.Cater.Where(c => c.cater_id == caterId).FirstOrDefault();

 //Remove him from Table Menu_Cater
 menu.Cater.Remove(cater);
 db.SaveChanges();

 return somethere...
}

多数民众赞成。它适用于MVC4

插入＆amp;删除多对多关系表中的值

2 个答案: