Searching inside embedded documents is exactly like searching inside hashes. This seems to make sense because MongoDB saves every document as a hash.

The following is an example of an embedded document:

{
"_id" : ObjectId("6234a68bfed0eb0beabcd234"),
"name" : "The Adventures of Sindbad",
"category" : {
"_id" : ObjectId("5ad6f68bfed0eb0be1231213"),
"name" : "Adventure",
}
}

To fetch the category object it's exactly the same way as searching inside a hash:

> db.books.find( { "category.name" : "Adventure" }

And just like that, searching inside arrays, hashes, and embedded documents have almost the same syntax!