[Boost-users] multi_index_container for composite key

Hi I am looking for a composite key container. Though I found multi_index_container for composite key is the best I have few doubts in its use case: Question:01 class Book { public: size_t mID; size_t node[3]; }; How to add the below into multi_index_container? typedef multi_index_container< Book, indexed_by< ordered_unique< composite_key< Book, member<Book,size_t,&Book::node[0]>, member<Book,size_t,&Book::node[1]>, member<Book,size_t,&Book::node[2]> > >, ordered_unique< member<Book,size_t,&Book::mID> > >

beambook;

Question:02 My requirement is straight forward. I need to get the id by providing 3 nodes. Should I always need to create a data structure? [class Book] Can't I have something like below? typedef multi_index_container< size_t, indexed_by< ordered_unique< composite_key< size_t, size_t, size_t > >, ordered_unique< size_t > >

beambook;

Thanks, UJ