||Query builder for ODM.
||Utility class for merging query criteria.
||Query expression builder for ODM.
||Class responsible for extracting an array of field names that are involved in a
given mongodb query. Used for checking if query is indexed.
||Collection class for all the query filters.
||ODM Query wraps the raw Doctrine MongoDB queries to add additional functionality
and to hydrate the raw arrays of data to Doctrine document objects.