>From what I understang, GAE always 'SELECT *', there is no way we could specify what property to select. If it is true you got memory error that quickly, then either you have tons of properties or there is a problem with GAE. Anyone else experiencing memory error that quick?
On Sep 11, 10:04 am, GAEfan <[EMAIL PROTECTED]> wrote: > 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 -~----------~----~----~----~------~----~------~--~---
