使用Fluent API进行级联删除 [英] Cascade delete using Fluent API

问题描述

我有两个实体。 个人资料和 ProfileImages 。提取个人资料后，我要通过个人资料删除 ProfileImages 没有它，只需删除对个人资料的引用（将其设置为 null ）。如何使用流畅的API和级联删除？是否要设置具有必需的属性或 CascadeDelete 属性？

I have two entities. Profile and ProfileImages. After fetching a Profile I want to delete ProfileImages through Profile without it just removing the reference to Profile (setting it to null). How can this be done with fluent API and Cascading Delete? Do I set the HasRequired attribute or the CascadeDelete attribute?

public class Profile 
{
    //other code here for entity
    public virtual ICollection<ProfileImage> ProfileImages { get; set; }
}

public class ProfileImage 
{
    // other code here left out        
    [Index]
    public string ProfileRefId { get; set; }

    [ForeignKey("ProfileRefId")]
    public virtual Profile Profile { get; set; }
}

推荐答案

您可以将其添加到您的 DB上下文：

You can add this to your DB Context:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<Profile>()
    .HasOptional(c => c.ProfileImages)
    .WithOptionalDependent()
    .WillCascadeOnDelete(true);
}

在此处了解更多信息： 启用级联删除

Read more here:Enabling Cascade Delete

您可以使用
WillCascadeOnDelete方法在关系上配置级联删除。如果从属实体
上的外键不可为空，则Code First将在
关系上设置级联删除。如果从属实体上的外键可以为空，则
Code First不会在关系上设置级联删除，并且当删除
主体时，外键将设置为null。

You can configure cascade delete on a relationship by using the WillCascadeOnDelete method. If a foreign key on the dependent entity is not nullable, then Code First sets cascade delete on the relationship. If a foreign key on the dependent entity is nullable, Code First does not set cascade delete on the relationship, and when the principal is deleted the foreign key will be set to null.

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