You write some LINQ code to update your SQL tables like this below BUT it does not throw an exception and it does not Update the tables!

using (var db=new SomeDatabaseContext())
{
     db.SomeTable
       .Where(x=>ls.Contains(x.friendid))
       .ToList()
       .ForEach(a=>a.status=true);

     db.SubmitChanges();
}

The reason why is because your Table does not have a Primary Key! You can update your DBML designer to have that Primary Key and you don't need to touch the actual SQL Server tables for this to work!

Best of Luck.