Question

我正在使用EF代码第一个模型。我有3个表Teacher，Student和Address。每位教师和学生都可以拥有多个地址，因此Teacher_Address和Student_Address之间的关联是 1到多。

为此，我写道：

public class Teacher 
{
 public int Id;

 public virtual List<Address> Addresses { get; set; }
}

public class Student 
{
 public int Id;

 public virtual List<Address> Addresses { get; set; }
}

public class Address
{
 public int Id;

 public int? TeacherId { get; set; }
 public virtual Teacher Teacher { get; set; }

 public int? StudentId { get; set; }
 public virtual Student Student { get; set; }
}

流利的Api：

        //Creating 1 to * relationships b\w Teacher and Address
        modelBuilder.Entity<Address>().HasOptional(p => p.Teacher)
                                      .WithMany(p => p.Addresses)
                                      .HasForeignKey(p => p.TeacherId)
                                      .WillCascadeOnDelete();

        //creating 1 to * replationship b\w Student and Address
        modelBuilder.Entity<Address>().HasOptional(p => p.Student)
                                      .WithMany(p => p.Addresses)
                                      .HasForeignKey(p => p.StudentId)
                                      .WillCascadeOnDelete();

我可以插入Teacher和Student的数据而没有任何问题但是当我尝试删除Teacher和Student中的任何一行时，它会显示以下内容例外：

DELETE语句与REFERENCE约束“FK_dbo.Address_dbo.Teacher_TeacherId”冲突。冲突发生在数据库“CodeFirst.TestContext”，表“dbo.Address”，列'TeacherId'。

有人可以告诉我如何解决这个问题以及我做错了什么？

Answer 1

似乎这种关系是倒退的。教师和学生不应该参考地址。我认为如果你删除地址条目（这不是我想你想要的），级联将正常工作。尝试将地址ID添加到其他实体，看看是否有效。

这样的事情：

public class Teacher 
{
 public int Id;

 public virtual List<Address> Addresses { get; set; }
}

public class Student 
{
 public int Id;

 public virtual List<Address> Addresses { get; set; }
}

public class Address
{
 public int Id;

}

流利的api：

modelBuilder.Entity<Teacher>().HasMany(p => p.Addresses)
                                  .WillCascadeOnDelete();

DELETE语句与sql中的REFERENCE约束冲突？

1 个答案: