使用PK删除表行以及其他表中有外键的行

Question

I have a method that deletes a user from my Users table by userId:

public void DeleteUser(int id)
    {
        User delObj = (Users.Where(u => u.UserId == id)).Single();
        Users.Remove(delObj);
        SaveChanges();
    }

The primary key userId is also used as a foreign key in a userroles table where there is a UserRoleId (PK), UserId (FK), and RoleId (FK). I am unsure how to knock out both rows in both tables with one method.

Thanks in advance!

Here are the exact properties:

public class User
{
    [Key]
    public int UserId { get; set; }
    public string UserName { get; set; }

    public virtual ICollection<UserRole> UserRoles { get; set; }
}



public class UserRole
    {
        [Key]
        public int UserRoleId { get; set; }
        public int UserId { get; set; }
        public short RoleId { get; set; }

        public virtual Role Role { get; set; }
    }

Answer 1

Implement the relation between your entities in c#. For example make the collection of Roles entities on User object. The ORM (I guess you are using EntityFramework or NHibernate) will take care of removing dependant objects automatically.

class User {
     public virtual ICollection<UserRole> UserRoles { get; set; }
}

It should be mapped as many to many relation.

And on your DBContext you must add:

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>()
            .HasMany(u => u.UserRoles)
            .WithOptional().WillCascadeOnDelete(true);
        base.OnModelCreating(modelBuilder);
    }