Is tabela.valor_blob a Blob field? The GAE documentation says projections can only include indexed properties, so no Text or Blob properties -- see https://developers.google.com/appengine/docs/python/datastore/queries#Query_Projection. I would think that would result in an error, though.
Anthony On Monday, June 11, 2012 9:35:28 PM UTC-4, Alex Benfica wrote: > > Hi Massimo and howesc! > > Testing again... I found a problem: > > Do not return errors ( but returns no rows... ). > rows = self.db(self.tabela.nome == nome).select(self.tabela.valor, > self.tabela.valor_blob) > > Returns the desired rows... > rows = self.db(self.tabela.nome == nome).select() > > > > > > > On Monday, June 11, 2012 10:10:18 PM UTC-3, Alex Benfica wrote: >> >> Hello people! >> >> First of all... thank you Massimo and howesc! >> >> About this question that I did and Massimo and howesc answerd on Stack >> Overflow. >> I tried to put some code there... but I could't... >> >> >> http://stackoverflow.com/questions/10940995/does-google-app-engine-projection-queries-are-supported-by-web2py >> >> I did the web2py update to trunk and some parts of my code stopped >> working. >> Most of problems I got where like this below, that I still don't know how >> to solve and keep it efficient, as I need to find the values by "name", not >> by id. >> >> I order to make it work, I just removed the fields I specified. >> >> Was this way (causing errors) >> self.db(self.tabela.nome == nome).select(self.tabela.valor, >> self.tabela.valor_blob, self.tabela.nome) >> >> I did that... now it selects all fields again... but works! >> self.db(self.tabela.nome == nome).select() >> >> I'm problably missing something! How can I use projection queries with >> web2py? The ID field that web2py creates are the same ID used by datastore >> on GAE? >> I have a product that I need find by name... can I query it using >> projection queries? Is that? >> >> >> >> >> rows = self.db(self.tabela.nome == nome).select(self.tabela.valor, >> self.tabela.valor_blob, self.tabela.nome) >> File "D:\Dropbox\Devel\www\web2py\gluon\dal.py", line 8161, in select >> return adapter.select(self.query,fields,attributes) >> File "D:\Dropbox\Devel\www\web2py\gluon\dal.py", line 4149, in select >> for t in fields] for item in items] >> File "C:\Program Files >> (x86)\Google\google_appengine\google\appengine\ext\db\__init__.py", line >> 2313, in next >> return self.__model_class.from_entity(self.__iterator.next()) >> File "C:\Program Files >> (x86)\Google\google_appengine\google\appengine\datastore\datastore_query.py", >> >> line 2809, in next >> next_batch = self.__batcher.next() >> File "C:\Program Files >> (x86)\Google\google_appengine\google\appengine\datastore\datastore_query.py", >> >> line 2671, in next >> return self.next_batch(self.AT_LEAST_ONE) >> File "C:\Program Files >> (x86)\Google\google_appengine\google\appengine\datastore\datastore_query.py", >> >> line 2708, in next_batch >> batch = self.__next_batch.get_result() >> File "C:\Program Files >> (x86)\Google\google_appengine\google\appengine\api\apiproxy_stub_map.py", >> line 604, in get_result >> return self.__get_result_hook(self) >> File "C:\Program Files >> (x86)\Google\google_appengine\google\appengine\datastore\datastore_query.py", >> >> line 2450, in __query_result_hook >> self._batch_shared.conn.check_rpc_success(rpc) >> File "C:\Program Files >> (x86)\Google\google_appengine\google\appengine\datastore\datastore_rpc.py", >> line 1214, in check_rpc_success >> raise _ToDatastoreError(err) >> BadRequestError: cannot use projection on a property with an equality >> filter >> >
