You'll want to read these articles:

http://code.google.com/appengine/articles/datastore/overview.html

<http://code.google.com/appengine/articles/datastore/overview.html>Stored
entities are sparse and schemaless, so Model and Expando classes are really
just a loosely-typed way to represent this data. Have you tested this out?
This seems like a fairly trivial example to try and observe.

On Sat, Mar 27, 2010 at 12:40 PM, dhruvbird <[email protected]> wrote:

> Hello,
>  I had a few questions about the appengine data store.
>
> 1. Is there any way to tell the data store to not index expando's
> dynamic properties?
> 2. Suppose I have a model:
> class Foo(db.Expando):
>  mem1 = db.IntegerProperty(indexed=True, blah..)
>
> Then, I add the attribute mem2 (at runtime):
> foo = Foo(mem1=100)
> foo.mem2=200
> foo.put()
>
> And then run a task queue which adds mem2 for every entity of kind Foo
> that doesn't have it.
> All future entities created will always have it (say):
> foo = Foo(mem1=blah, mem2=blah-blah)
> foo.put()
>
> Now, I redefine class Foo as:
> class Foo(db.Expando):
>  mem1 = db.IntegerProperty(indexed=True, blah..)
>  mem2 = db.IntegerProperty(indexed=False, blah)
>
> What will happen if I upload this new definition and use it with the
> same data in the data store?
>
> Also, what will happen if the type of mem2 is changed from
> IntegerPropery to StringProperty, but the mem2 attributes has only
> Integers stored?
>
> Regards,
> -Dhruv.
>
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>


-- 
Ikai Lan
Developer Programs Engineer, Google App Engine
http://googleappengine.blogspot.com | http://twitter.com/app_engine

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