$returnKey
Deprecated since v3.2
Starting in v3.2, the $returnKey
operator is deprecated in themongo
shell. In the mongo
shell,use cursor.returnKey()
instead.
Only return the index field or fields for the results of the query. If$returnKey
is set to true
and the query does not usean index to perform the read operation, the returned documents willnot contain any fields. Use one of the following forms:
- db.collection.find( { <query> } )._addSpecial( "$returnKey", true )
- db.collection.find( { $query: { <query> }, $returnKey: true } )