EF代码首先级联删除外键一对多 [英] EF Code first cascade delete on foreign key one-to-many

问题描述

我们正在实体框架代码中工作

We are working in Entity framework Code first

我们有一个类视频

class Video{
   List<ImageInfo> Images{
      get; set;
   }
}

我们的图像infoclass包含图像的路径和一些其他信息

our image infoclass contains a path to the image and some other info

class ImageInfo{
    String path;
    ...
}

我们想要EF删除imageinfos删除视频

we would like to have EF remove the imageinfos when removing the video

所以我们改变了模型制作者，如下所示：

so we changed the modelbuilder like follows:

modelBuilder
    .Entity<Video>()
    .HasMany(v => v.Images)
    .WithRequired()
    .WillCascadeOnDelete(true);

我们不想在imageinfo类中添加回到视频的链接。

we don't want to add a link back to video in our imageinfo class.

是否可以在没有2路外键的情况下获得级联删除功能？

is it possible to get cascade delete functionality without a 2 way foreign key?

编辑

保存视频时，imageInfo的video_id不会在数据库中填写。

the video_id of the imageInfo doesn't get filled in in the database when saving a video.

http://pbrd.co/14X82vb

我们如何解决这个问题？

how can we fix this?

我不知道它是否相关，但是当我们同时添加一个带有图像的新视频时，我们得到这个错误：

I don't know if its related, but when we add a new video with images at the same time, we get this error:

Unable to determine a valid ordering for dependent operations. Dependencies may exist due to foreign key constraints, model requirements, or store-generated values.

推荐答案

WithRequired 介绍了2路关系。所以你应该执行以下操作。

The WithRequired introduces the 2 way relationship. So you should do the following.

modelBuilder
    .Entity<Video>()
    .HasMany(v => v.Imgages)
    .WithOptional()
    .WillCascadeOnDelete(true);

...假设你想要的关系是相反的...

... and assuming you want the relationship the other way around ...

public class Video { }
public class ImageInfo {
    public virtual Video { get; set; }
}

modelBuilder
    .Entity<ImageInfo>()
    .HasRequired(v => v.Video)
    .WithMany()
    .WillCascadeOnDelete(true);

PS：我认为列表< ImageInfo> 应该是 virtual ，所以这里是我如何定义它...

PS: I think the List<ImageInfo> should be virtual, so here is how I'd define it ...

public class Video {
    public Video() { this.Images = new List<ImageInfo>(); }
    public virtual ICollection<ImageInfo> Images { get; set; }
}

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