引用约束错误删除具有集合导航属性的派生类型 [英] Reference constraint error deleting derived type having collection navigation property

问题描述

我得到  DELETE语句与REFERENCE约束冲突 错误尝试删除包含其他对象列表的对象  ; 和 从映射到单独表的其他类型派生
。

I get a The DELETE statement conflicted with the REFERENCE constraint error trying to delete an object that contains a list of other objects and derives from an other type that is mapped to a separate table.

Here是我的类型：

Here are my types:

public class Base
{
    public int Id { get; set; }
}

public class Main : Base
{
    public virtual IList<ListItem> ListItems { get; set; }
}

public class ListItem
{
    public int Id { get; set; }

    public int MainId { get; set; }
    public virtual Main Main { get; set; }
}

配置：

configuration:

public DbSet<Base> Bases { get; set; }
public DbSet<Main> Mains { get; set; }
public DbSet<ListItem> ListItems { get; set; }

modelBuilder.Entity<Base>().ToTable("SomeTable");
modelBuilder.Entity<Main>().HasKey(x => x.Id)
               .HasMany(x => x.ListItems)
               .WithRequired(x => x.Main)
               .WillCascadeOnDelete();

我删除Main的方式：

The way I delete Main:

context.Entry(context.Main.First()).State = EntityState.Deleted;
context.SaveChanges();

如果基类是  not mapped  到表。这非常奇怪。我在这里做错了什么？我试过覆盖Base类型的Id属性，我甚至尝试移动
Id属性为Main类型并将其从Base中删除，但没有运气。

I don't get any error if Base class is not mapped to a table. This is extremely weird. What am I doing wrong here? I tried overriding the Id property of the Base type, I even tried moving the Id property to the Main type and removing it from the Base altogether, but no luck.

推荐答案

嗨ewzer，

Hi ewzer,

根据您的描述和代码片段，我们知道，实体框架依赖于每个具有用于跟踪实体的密钥值的实体。从您的代码中，我找不到名为Main的模型上的任何键。我检索到这样的错误：

Based on your description and code snippet, As we know, Entity Framework relies on every entity having a key value that it uses for tracking entities. From your code, I could not find any key on model named Main. I retrieve a error like this:

请修改您的模型如下：

public class Main : Base
{
    public virtual IList<ListItem> ListItems { get; set; }
}

或

public class Main
{

public int Id {get; set;}
公共虚拟IList< ListItem> ListItems {get;组; }
}

public int Id { get; set; } public virtual IList<ListItem> ListItems { get; set; } }

祝你好运，

Cole Wu

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