Question

Resource通过Action联接表/单独实体与Permission M ： M 相关联。用户可以拥有许多命名权限。可以为多个用户分配相同的权限。

如何将User - Permission关系定义为 M ： M ？它在 EF 中会是什么样子？

修改

我应该将ResourceId和ActionId合并为 EF 中的主键吗？
如何将Permission与User关联呢？
如何进行插入/选择？

将它映射成是正确的：

modelBuilder.Entity<User>()
    .HasMany(u => u.Permissions)
    .WithMany(p => p.Users)
    .Map(c => {
        c.MapLeftKey("ResourceId");
        c.MapLeftKey("ActivityId");
        c.ToTable("UserPermissions");
     });

如果Permission的定义如下：

public class Permission {
    public String Name { get; set; }

    public Int32 ResourceId { get; set; }
    public virtual Resource Resource { get; set; }

    public Int32 ActivityId { get; set; }
    public virtual Activity Activity { get; set; }

    public virtual ICollection<User> Users { get; set; }
}

和User喜欢这样：

public class User : Entity {
    public String Username { get; set; }
    public String UserImagePath { get; set; }
    public String Password { get; set; }
    public virtual ISet<Permission> Permissions { get; set; }

    public User(String username, String password) {
        this.Username = username;
        this.Password = password;
        this.Permissions = new HashSet<Permission>();
    }
}

Answer 1

要在User和Permission之间创建多对多关系，您需要创建ICollection<>类型的两个navegation属性：

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Password { get; set; }

    public virtual ICollection<Permission> Permissions { get; set; }
}

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

    public int ResourceId { get; set; }
    public virtual Resource Resource { get; set; }

    public int ActionId { get; set; }
    public virtual Action Action { get; set; }

    public virtual ICollection<User> Users { get; set; }
}

Code First约定将承认多对多关系并使用表的相应键在数据库中构建连接表加盟。键是连接表的主键和指向的外键连接表。通过组合名称来创建新表的名称它正在加入的类，然后使结果多元化。

如果您愿意自己这样做，可以使用Fluent Api来完成。一种简单的方法是覆盖Context的OnModelCreating方法。我在下面举例说明了你的情况：

 protected override void OnModelCreating(DbModelBuilder modelBuilder)
 {
        modelBuilder.Entity<User>().HasKey(p => p.Id);
        modelBuilder.Entity<User>().Property(u => u.Name).IsRequired();
        modelBuilder.Entity<User>().Property(u => u.Password).IsRequired();

        modelBuilder.Entity<Permission>().HasKey(p => p.Id);
        modelBuilder.Entity<Permission>().Property(u => u.Name).IsRequired();

        //configuring the many-to-many relationship
        modelBuilder.Entity<User>()
            .HasMany(u => u.Permissions)
            .WithMany(p => p.Users)
            .Map(c => c.ToTable("UserPermissions"));
 }

如您所见，您可以使用Fluent Api来指定您的人际关系。此外，您可以指定哪个适当的主要密钥，如果需要某个属性，依此类推。所有这些都可以使用Data Annotations来完成。

Answer 2

为了在User和Permission之间建立多对多关系，只需添加相应的集合。在用户和权限集合中添加权限集合。

像

这样的东西

User
...
...
<ICollection> Permissions

Permissions
....
....
<ICollection> Users

这有望添加一个新表，如PermissionsUsers或UsersPermissions。

Answer 3

这是我得到的：

<强>的DbContext

public class AppDbContext : DbContext {
    public DbSet<User> Users { get; set; }
    public DbSet<RoleResourceActivity> RoleResourceActivities { get; set; }
    public DbSet<Activity> Activities { get; set; }
    public DbSet<Resource> Resources { get; set; }
    public DbSet<Role> Roles { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder) {
        modelBuilder.Entity<Activity>().HasKey(i => i.Id);
        modelBuilder.Entity<Resource>().HasKey(i => i.Id);
        modelBuilder.Entity<User>().HasKey(i => i.Id);
        modelBuilder.Entity<RoleResourceActivity>().HasKey(i => new {
            i.ResourceId, 
            i.ActivityId, 
            i.RoleId
        });

        base.OnModelCreating(modelBuilder);
    }

    public AppDbContext() : base("AppDb") { 
        Database.SetInitializer<AppDbContext>(new AppDbContextInitializer());
    }
}

<强>模型

public class RoleResourceActivity {
    public Int32 ResourceId { get; set; }
    public virtual Resource Resource { get; set; }

    public Int32 ActivityId { get; set; }
    public virtual Activity Activity { get; set; }

    public Int32 RoleId { get; set; }
    public virtual Role Role { get; set; }
}

public class User {
    public Int32 Id { get; set; }
    public String Username { get; set; }
    public String UserImagePath { get; set; }
    public String Password { get; set; }

    public virtual ISet<Role> Roles { get; set; }

    public User(String username, String password) : this() {
        this.Username = username;
        this.Password = password;
    }

    protected User() { 
        this.Roles = new HashSet<Role>();
    }
}

public class Role {
    public Int32 Id { get; set; }
    public String Name { get; set; }
    public virtual ISet<User> Users { get; set; }
    public virtual ISet<RoleResourceActivity> RoleResourceActivities { get; set; }

    public Role(String name) : this() { 
        this.Name = name;
    }

    protected Role() {
        this.Users = new HashSet<User>();
        this.RoleResourceActivities = new HashSet<RoleResourceActivity>();
    }
}

public class Resource {
    public Int32 Id { get; set; }
    public String Name { get; set; }
    public virtual ISet<RoleResourceActivity> RoleResourceActivities { get; set; }

    public Resource(String name) : this() {
        this.Name = name;
    }

    protected Resource() {
        this.RoleResourceActivities = new HashSet<RoleResourceActivity>();
    }
}

public class Activity {
    public Int32 Id { get; set; }
    public String Name { get; set; }
    public virtual ISet<RoleResourceActivity> RoleResourceActivities { get; set; }

    public Activity(String name) : this() {
        this.Name = name;
    }

    protected Activity() {
        this.RoleResourceActivities = new HashSet<RoleResourceActivity>();
    }
}

如何将用户/权限关系定义为M：M？

3 个答案: