c# - 为所有实体设置级联删除

Question

我正在尝试为我的所有实体配置 DeleteBehavior。最终结果是我可以简单地运行:

DELETE FROM Companies Where Id = '1'

我所有的 800 个表都将在级联中被清理(所有表引用 CompanyId as FK)...

我的类(class)

public interface ITest
{
    string PropX { get; set; }
    Company Company { get; set; }
}

public abstract class Reg {
    public int Id { get; set; }
    public Company Company { get; set; }
}

public class Company {
    public int Id { get; set; }
    public string Name { get; set; }
}


public class Test : Reg, ITest
{
    public string Prop1 { get; set; }
    public string PropABC { get; set; }
    public string PropX { get; set; } = "My Info";
}

public class Test2 : Reg, ITest
{
    public string PropEFG { get; set; }
    public string PropX { get; set; } = "My Info2";
}

public class Test3 : Reg, ITest
{
    public string PropExample { get; set; }
    public string PropX { get; set; } = "My Info3";
}

如果我这样做，效果完美:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);
    modelBuilder.Entity<Test>().HasOne(p=>p.Company).WithMany().OnDelete(DeleteBehavior.Cascade);
    modelBuilder.Entity<Test2>().HasOne(p=>p.Company).WithMany().OnDelete(DeleteBehavior.Cascade);
    //....... not for 800 classes

 }

但我有 800 个类(class)...所以我正在尝试这样做:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    var my800Entities = modelBuilder.Model.GetEntityTypes().ToList();

    foreach (var entity in my800Entities)
    {
       modelBuilder.Entity(entity.Name).HasOne("Company").WithMany().OnDelete(DeleteBehavior.Cascade);
       /* It seems to me that this code is creating an
       extra column and not defining the already existing property */
    }

}

上面的代码在每个类中生成一个多列的迁移，示例:

• 其他属性...
• 公司(FK限制删除行为)
• Company1(具有 FK 级联删除行为)

对于具有级联删除行为的 1 列(公司)，我需要做什么？

Answer 1

首先过滤实现接口(interface)的实体类型:

var my800Entities = modelBuilder.Model.GetEntityTypes()
    .Where(t => typeof(ITest).IsAssignableFrom(t.ClrType))
    .ToList();

然后(这是您代码的主要问题)，将相关类型和导航属性名称都传递给 HasOne 方法(目前您只传递相关类型名称，相当于无参数泛型 HasOne 并指示关系没有导航属性，因此 EF Core 将另一个关系与该属性相关联):

foreach (var entity in my800Entities)
{
    modelBuilder.Entity(entity.Name)
       .HasOne(typeof(Company), "Company") // <--
       .WithMany()
       .OnDelete(DeleteBehavior.Cascade);
}