I have two collections. One is students and the other is books. Students may select up to 100 books. So, I may design students collection as
{
'_id'=>'',
selections['bookid1', 'bookid2', 'bookid3' ... so on]
}
And another solution would be a selections collections
{
'_id'=>''
'book_id'=>'',
'student_id'=>''
}
Which design is better in terms of query performance. Is there any other reason to choose one over the other?