如何删除实体在许多一对多关系使用波苏斯 [英] How to delete entity in many-to-many relationship using POCOs

问题描述

我在EF4结合使用波苏斯和一些实体在许多一对多的关系，在课堂上用户和类PrivilegeGroup的对象，我的情况的对象。

I'm using POCOs in combination with EF4 and some entities are in many-to-many relationships, in my case objects of class User and objects of class PrivilegeGroup.

这是类用户的样子：

public class User
{
    public int UserID { set; get; }
    public string UserName { get; set; }
    public string UserPassword { get; set; }
    public bool IsActive { get; set; }

    public List<PrivilegeGroup> PrivilegeGroups { get; set; }
}

这是类PrivilegeGroup的样子：

And this is how class PrivilegeGroup looks like:

public class PrivilegeGroup
{
    public int PrivilegeGroupID { get; set; }
    public string Name { get; set; }

    public List<User> Users { get; set; }
    public List<HasPrivilege> HasPrivileges { get; set; }
}

我已经延长ObjectContext类
，如下所示：

I have extended ObjectContext class as follows:

public class AdminMDSContext : ObjectContext
{

    public AdminMDSContext(string connectionString)
        : base(connectionString)

    {
        this.DefaultContainerName = "MDSUsers_Entities";
        _users = CreateObjectSet<User>();
        _privilegeGroups = CreateObjectSet<PrivilegeGroup>();

    }


    private ObjectSet<User> _users;
    private ObjectSet<PrivilegeGroup> _privilegeGroups;

    public ObjectSet<User> Users
    {
        get { return _users; }
    }


    public ObjectSet<PrivilegeGroup> PrivilegeGroups
    {
        get { return _privilegeGroups; }
        set { _privilegeGroups = value; }
    }

}

查询和这些实体的插入工作正常，但缺失使得问题，即我想从一个用户无需分贝往返删除PrivilegeGroup，但我不知道该怎么办了。

Querying and insertion of these entities are working fine, but deletion is making problem, i.e. I want to remove PrivilegeGroup from one User without db roundtrip, but I don't know how to do it.

灿有人帮帮我吗？

推荐答案

有趣的问题。这里为u如何做到这一点。

Interesting question. Here is how u do it.

var user = new User { UserId = 1 };
var admin = new Privilege { PrivilegeId = 1 };
user.Privileges.Add(admin);
db.Users.Attach(user);
user.Privileges.Remove(admin);
db.SaveChanges();

有共计4种不同的方法来解决同样的问题。但是我觉得从什么ü告诉我，这应该足够了，但如果u需要更多的信息，你可以直接ping通我通过邮件

There are total of 4 different approaches to solving the same problem. but i think from what u are telling me, this should suffice but if u need more info, you can ping me directly through mail

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