Removing a child entity

01-Example.cs

var context = new MyContext();
var parent = context.Parents.Include("Children").SingleOrDefault(x => x.ParentId == 1);
var child = parent.Children.First();

var parent.Childred.Remove(child);     // Is this step necessary?
var context.Childred.Remove(child);    // Or is this alone sufficient?

context.SaveChanges();

02-Entities.cs

public class Parent
{
    public int ParentId { get; set; }
    public virtual ICollection<Child> Children { get; set; }
}

public class Child
{
    public int ChildId { get; set; }
    public in ParentId { get; set; }
    public virtual Parent Parent { get; set; }
}

public MyContext : DbContext
{
    public DbSet<Parent> Parents { get; set; }
    public DbSet<Child> Children { get; set; }
}