Lab: Tree Patterns

Hi.

I don’t know why in the tree pattern’s lab the best option is not child references.

I mean, we want to know all the direct reports of an employee efficiently. This is the best option because we have all the people that report to us only accesing to a document, avoiding mongoDb accesing other documents and indexes.

Also, we could know who is our manager, altough it is more complicated query (but the problem didn’t have a constraint about it).

Can you explain me better? Thank you.