Just star'd it -thx. 2009/6/24 Jeff S (Google) <j...@google.com>: > Hi Jeff, > > This is an idea that we're aware of as well. If you could reserve the next > ID in advance, then you could actually do this in one put since multiple > entities could be sent in one batch :-) The workaround available now is to > use the key_name, but the difficulty becomes ensuring that the key_name is > unique. Here is a feature request which I'm aware of which is along these > lines (though the approach differs slightly): > > http://code.google.com/p/googleappengine/issues/detail?id=1003 > > Thank you, > > Jeff > > 2009/6/24 Jeff Enderwick <jeff.enderw...@gmail.com> >> >> Hey Jeff - sorry for the confusion. The idea was that one would be >> able to get the unique id from an GOOG and then do a db.put with that >> id as an arg. For example, let's say I want to create two entities, >> with each referring to each other. I need to do three db.put >> operations: >> >> a = Foo() >> db.put(a) >> b = Foo() >> b.ref = a.key() >> db.put(b) >> a.ref = b.key() >> db.put(a) >> >> One would hope to be able to do this with two db.puts. >> >> Thanks, >> Jeff >> >> >> 2009/6/16 Jeff S (Google) <j...@google.com>: >> > >> > The datastore does not allow key_names which begin with a digit in >> > order to avoid confusion with an ID, which is numerical. If you want >> > to use numeric key names, you could add a one letter prefix :-) >> > >> > Happy coding, >> > >> > Jeff >> > >> > On Jun 16, 1:17 am, cryb <cbuti...@gmail.com> wrote: >> >> Hi Jeff. >> >> Thanks for your reply.. I really hope that in the near future >> >> appengine will support setting key ids for entities. >> >> You mentioned that I can use hooks in order to achieve my goal.. >> >> However I was more interested in a solution based on appengine java >> >> sdk, and not on python hooks. Does appengine java sdk provide hooks or >> >> some other similar mechanism? >> >> It seems that for the moment I'll stick to generating key names. >> >> One more question: I've tried to generate some entities with key names >> >> on my local devappserver and I got a strange exception stating that I >> >> can't create key names that start with a digit (?!?)... this holds on >> >> google appengine production servers too or it's just a "bug" of >> >> devappserver? >> >> >> >> Thanks >> >> >> >> On Jun 16, 2:45 am, "Jeff S (Google)" <j...@google.com> wrote: >> >> >> >> > Hi cryb, >> >> >> >> > As you noted, we do not currently allow the ID for a key to be set, >> >> > as we >> >> > ensure that the ID is unique for each existing entity. I recommend >> >> > using a >> >> > key name instead of an ID, as Antoniov suggeted, if possible. >> >> >> >> > It is technically possible to modify the key of an entity as it is >> >> > being >> >> > converted to a protocol buffer message before it is sent to the >> >> > datastore. >> >> > You could do this using hooks in the API proxy as described in this >> >> > article:http://code.google.com/appengine/articles/hooks.htmlAlsoit is >> >> > possible to >> >> > construct the key for the desired object if you know the ID in >> >> > advance. >> >> >> >> > class X(db.Model): >> >> > pass >> >> >> >> > # If you've already created the entity so you have the ID. >> >> > x_id = X().put().id() >> >> >> >> > # Instead of getting by ID, you can create the key manually. >> >> > k = db.Key.from_path('X', x_id) >> >> >> >> > Now you have the desired key without having fetched the object, but >> >> > the part >> >> > which the model class does not allow is setting the key yourself. So >> >> > you >> >> > could modify the protocol buffer message before it is written to the >> >> > datastore, but I don't recommend it. >> >> >> >> > The decision to allow setting key_names but not IDs is something we >> >> > may >> >> > revisit. >> >> >> >> > Happy coding, >> >> >> >> > Jeff >> >> >> >> > 2009/6/12 cryb <cbuti...@gmail.com> >> >> >> >> > > Hi.. that is to build key names... What I asked was why I can't >> >> > > build >> >> > > a key ID.. >> >> >> >> > > On Jun 12, 5:35 am, Antoniov <nio....@gmail.com> wrote: >> >> > > > Use the code: >> >> > > > s = Story(key_name="xzy123") >> >> > > > Then you create an entity with the key name "xzy123". >> >> >> >> > > > Check this: >> >> > >> >> > > >http://code.google.com/intl/en-US/appengine/docs/python/datastore/key... >> >> >> >> > > > On 6月12日, 上午1时28分, cryb <cbuti...@gmail.com> wrote: >> >> >> >> > > > > Does anyone know why it is possible to build a key name but NOT >> >> > > > > a key >> >> > > > > id? I know key IDs are used as autoincrements, but why can't I >> >> > > > > just >> >> > > > > override this mechanism and build my own key id? >> >> > > > > Suppose I want to overwrite an existent entry in my table that >> >> > > > > has a >> >> > > > > key id I know, and also I want to keep that key id after >> >> > > > > update... >> >> > > > > because I can't just build a key id, I am forced to fetch that >> >> > > > > entity, >> >> > > > > modify it and write it back, instead of just write the updated >> >> > > > > entity >> >> > > > > with the key id I already know - so an additional read to the >> >> > > > > datastore. >> >> > > > > Is there an obscure reason for that? (both key names and key >> >> > > > > ids are >> >> > > > > prefixed with appid/kind as far as I know so there is no chance >> >> > > > > of >> >> > > > > collision with other apps/kinds) >> > > >> > >> >> > > > > >
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