指定ON DELETE在ASP.NET MVC 4 C＃code首先NO ACTION [英] Specify ON DELETE NO ACTION in ASP.NET MVC 4 C# Code First

问题描述

我如何指定ON DELETE NO ACTION外键约束在我的模型设计？

How do I specify ON DELETE NO ACTION Foreign Key Constraint in my model designs?

在present，我有：

At present, I have:

public class Status
{
    [Required]
    public int StatusId { get; set; }

    [Required]
    [DisplayName("Status")]
    public string Name { get; set; }
}

public class Restuarant
{
    public int RestaurantId { get; set; }
    [Required]
    public string Name { get; set; }
    [Required]
    [EmailAddress]
    public string Email { get; set; }
    [Required]
    public string Telephone { get; set; }
    [Required]
    public int StatusId { get; set; }
    public List<Menu> Menus { get; set; }

    // NAVIGATION PROPERTIES
    public virtual Status Status { get; set; }
}

public class Menu
{
    public int MenuId { get; set; }

    [Required]
    public int RestaurantId { get; set; }

    [Required]
    public string Name { get; set; }

    [Required]
    public int StatusId { get; set; }

    // NAVIGATION PROPERTIES
    public virtual Status Status { get; set; }
    public virtual Restaurant Restaurant { get; set; }
}

和我的DbContext：

And my DbContext:

public class MenuEntities : DbContext
{
    public DbSet<Status> Statuses { get; set; }
    public DbSet<Restaurant> Restaurants { get; set; }
    public DbSet<Menu> Menus { get; set; }
}

正如你所看到的：

As you can see:

• 餐厅有很多菜单


• 餐厅有一个状态


• Menu（菜单）属于一间餐厅


• 两个餐厅和菜单具有1的状态。 （现场，无形的，草案）

• a Restaurant has many menus
• a Restaurant has one status
• a Menu belongs to 1 restaurant
• Both Restaurants and Menus have 1 status. (Live, Invisible, Draft)

当然，如果一个状态被删除了，我当然不希望级联，因为这将淤泥一切。

Naturally, if a status is deleted, I certainly don't want to cascade as this will muck everything up.

更新：

标记Oreta提到使用下他的例子如下：

Mark Oreta mentions using the following in his example below:

modelBuilder.Entity<FirstEntity>() 
    .HasMany(f => f.SecondEntities) 
    .WithOptional() 
    .WillCascadeOnDelete(false); 

我在哪里可以把这个code？在我的MenuEntities /的DbContext类？
任何人可以提供这种被使用的例子？

Where do I put this code? Within my MenuEntities / DbContext class? Can anybody provide an example of this being used?

更新：
得到这个有点现在的工作，但是这已经创造试图播种DB时的多重约束错误...

UPDATE: Got this bit working now, however this has created a multiplicity constraint error when trying to seed the DB...

Multiplicity constraint violated. The role 'Menu_Status_Source' of the relationship 'LaCascadaWebApi.Models.Menu_Status' has multiplicity 1 or 0..1.

我的数据库初始化器：

My Database Initialiser:

http://pastebin.com/T2XWsAqk

推荐答案

您可以通过删除级联删除OnModelCreating方法的公约禁​​用它为您的整个背景：

You can either disable it for your entire context by removing the cascade delete convention in the OnModelCreating method:

  protected override void OnModelCreating( DbModelBuilder modelBuilder )
  {
     modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
  }

或者，你可以用流利的映射（也在OnModelCreating）做每关系：

or, you can do it per relationship using a fluent mapping (also in the OnModelCreating):

编辑：你把它放在你的菜单实体

public class MenuEntities : DbContext
{
    public DbSet<Status> Statuses { get; set; }
    public DbSet<Restaurant> Restaurants { get; set; }
    public DbSet<Menu> Menus { get; set; }

      protected override void OnModelCreating( DbModelBuilder modelBuilder )
      {

         modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();

     modelBuilder.Entity<Menu>()
        .HasRequired( f => f.Status )
        .WithRequiredDependent()
        .WillCascadeOnDelete( false );

     modelBuilder.Entity<Restaurant>()
        .HasRequired( f => f.Status )
        .WithRequiredDependent()
        .WillCascadeOnDelete( false );

      }

}

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