Question

我需要以某种方式显式地忽略复杂类型的“深度”导航属性，或显式地告诉EF如何加入

我正在简单地选择用户并映射到平面视图模型（显然我已经为ProjectTo设置了相关的映射）：

from django.shortcuts import render
from django.http import HttpResponse
from .models import Courses

def homepage(request):
    cos = Courses.objects.all()
    context={ 'courses': cos }

    return render(request, "main/home.html", context)

像这样覆盖OnModelCreating方法适用于这种情况，但是显然将一直排除OwnerPerson，我们只想排除当从数据库中选择User实体并将其映射到UserModel时使用它：

return await DataContext.Users
    .ProjectTo<UserModel>()
    .ToListAsync();

public class User {
    public int PersonId { get; set; }       
    public Person Person { get; set; }
}
public class Person {
    public int Id { get; set; }     
    public int DeptartmentId { get; set; }      
    public Department Department { get; set; }
}
public class Department {
    public int Id { get; set; }     
    public int DeptartmentHeadId { get; set; }      
    public Person DepartmentHead { get; set; }
}
public class UserSummary
{
    public Guid Id { get; set; }
    public string UserName { get; set; }
    public string Name { get; set; }
    public string DepartmentName { get; set; }
}

我需要做类似的事情：

builder.Entity<Department>().Ignore(x => x.DepartmentHead);

使用SQL事件探查器，您可以看到它在部门上创建了意外连接：

builder.Entity<User>().Ignore(x => x.Person.Department.DepartmentHead);

我想要的是：

 SELECT * FROM [Users] AS [x] 
 INNER JOIN [dbo].[People] AS [x.Person]
 ON [x].[PersonId] = [x.Person].[Id] 
 LEFT JOIN [Departments] AS [x.Person.Department] 
 ON [x.Person].[Id] = [x.Person.Department].[DeptartmentHeadId]

Answer 1

我需要做的就是告诉EF部门有人员（因此确定关系映射）：

public class Department {
    public int Id { get; set; }     
    public int DeptartmentHeadId { get; set; }      
    public Person DepartmentHead { get; set; }

    [InverseProperty(nameof(Person.Department))]
    public IList<Person> People { get; set; } = new List<Person>();
}

如何防止EF Core在实体之间进行不正确的联接

1 个答案: