List<DBObject> rows = getAssociationRows( association, key );
DBObject update = new BasicDBObject( "$set", new BasicDBObject( associationField, rows ) );
collection.update( query, update, true, false, writeConcern );
}
@Override
public void removeAssociation(AssociationKey key, AssociationContext associationContext) {
AssociationStorageStrategy storageStrategy = getAssociationStorageStrategy( key, associationContext );