Going out on a limb here... think its a generics question
public IQueryable<T> ApprovedItems<T>(DbObject db)
where T : IApprovable
{
var query = db.Set<T>();
return query.Where(p => p.Approved == "N");
}
public interface IApprovable
{
//By the way I do not Approve of an
//approve flag with type of string
string Approved {get;}
}