Iteration support would be very useful.
For example the use of map can be a workaround for the absense of multi $(update) support during update operation (the update query must contain the simply the key of object to update), but since iteration over map is unsupported i can't $unwind the map or use any other array operator of mongodb.

So the only solution for my problem is to create a separate collection and "dbref" it... .' (RELATIONAL DB STYLE)