One major limitation of AppEngine is that you can only query the
datastore with a
'SELECT * FROM myData'
meaning you must put ALL properties of each entity into memory. This
gets you to a Memory error rather quickly, especially if you have many
properties for each entity. In my app, I can only query about 100
entities at a time, nowhere near the expected 1000.
I am trying to hack a form of
'SELECT PropertyOne FROM myData',
to just put that single property into memory (of course through a
broad range of many entities)
I was wondering if I could save memory by using a one-to-many format,
with ReferenceProperty. For example, my entities are keyed by date,
so I thought of trying something like this:
class myDate(BaseModel):
Date = db.DateProperty()
class PropertyOne(BaseModel):
Date = db.ReferenceProperty(myDate, collection_name='prop1_ref')
Value = db.FloatProperty()
...
etc. for each Property, each Ref'd to myDate.
My first question is: If I call ''SELECT * FROM myDate'', will it put
all of the Referenced Properties into memory? If so, that may kill
this idea, too.
Second, would this act like a way to query ONLY an individual
property, along with its Date? Something like ''SELECT * FROM
PropertyOne'' ? (using this method, there seems to be no reason to
reference the Property to myDate, just make several distinct Models.
But it would be great to tie them all to a single date when I pull
multiple properties.)
Thirdly, is there some other method of querying just a single
property, like myDate.PropertyOne, through a broad range of Dates,
without having to get all of the other properties crowding into
memory?
Hope that makes sense. Thanks.
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Google App Engine" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/google-appengine?hl=en
-~----------~----~----~----~------~----~------~--~---
