An interface for classes that know how to query an association
| Type | Name and description | 
|---|---|
| boolean | doesReturnKeys()@return Whether the query returns the keys for the entities or the enities themselves | 
| PersistentEntity | getIndexedEntity()@return The entity to be queried | 
| java.util.List<T> | query(K primaryKey)Queries the given primary key and returns the foreign keys | 
Queries the given primary key and returns the foreign keys
primaryKey -  The primary key