nested model serializer for django-mptt

[smcoll]

i'm using django-mptt for a hierarchical model in my app.  i've created a nested serializer for it, but it does not take advantage of MPTT's query efficiency.  It's instead simply using recursive queries.  i'd like to know if there's a way to make that optimization.

First a little background for those unfamiliar with MPTT:  django-mptt allows me to return an entire hierarchical tree in a single query, by ordering all the objects from "left to right" and returning their level (depth in tree) and parent.  For example, i have top-level object A which has three children: B, C, and D.  C has two children, E and F.   Myobject.objects.get_descendants(include_self=True) will return a queryset looking something like this: [<A level=0>, <B level=1>, <C level=1>, <E level=2>, <F level=2>, <D level=1>]  (each node has a 'parent' explicitly defined, as well).

The order of the queryset, along with the "level" information, is enough to draw out the tree structure.  For example:

>>> objectA = MyModel.objects.toplevel().first()  # get a root node

>>> for node in objectA.get_descendants(include_self=True):

...     print '%s%s' % (node.level * '--', node)

... 

Object A

--Object B

--Object C

----Object E

----Object F

--Object D

You can imagine what it might look like as a nested JSON object.

So my question is, how might i approach writing a nested model serializer that would work the same way, which would require a single query rather than three recursive queries?  Has anyone already solved this?

[Rukaya Johaadien]

Hi Smcoll, I'd be really interested in knowing what you did in the end to solve this. 

[Shannon Collins]

Unfortunately, we never made this optimization.  The project underwent a pretty significant change and we stopped using MPTT.

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