google-cloud-datastore

Regarding the code lab here , how can we filter datastore data within the mapreduce jobs rather than fetching all objects for a certain entity kind? In the mapper pipeline definition below, the only one input reader parameter is the entity kind to process and I can't see other parameters of type filter in the InputReader class that could help. output = yield mapreduce_pipeline.MapperPipeline( "Datastore Mapper %s" % entity_type, "main.datastore_map", "mapreduce.input_readers.DatastoreInputReader", output_writer_spec="mapreduce.output_writers.FileOutputWriter", params={ "input_reader":{ "entity

The Google App Engine Datastore allows each entity to have a parent entity , essentially a way to form an entity hierarchy . For example, an Employee can be addressed as: Company#521/Department#5/Employee#3 The entity id is only unique among entities with the same parent, so the full entity path is required to uniquely address it. So far, so good. But when should I model a parent-child relationship this way, rather than relying on a basic reference property within an entity, as I would in a traditional database? The only reason I can think of is to get around the lack of joins in a Datastore

Following up on my earlier question regarding GAE Datastore entity hierarchies , I'm still confused about when to use entity groups . Take this simple example: Every Company has one or more Employee entities An Employee cannot be moved to another Company , and users that deal with one Company can never see the Employee s of another Company This looks like a case where I could make Employee a child entity of Company , but what are the practical consequences? Does this improve scalability, hurt scalability, or have no impact? What are other advantages/disadvantages of using or not using an

What is the best/fastest way to check if an Entity exists in a google-app-engine datastore? For now I'm trying to get the entity by key and checking if the get() returns an error. I don't know the process of getting an Entity on the datastore. Is there a faster way for doing only this check? com.google.appengine.api has been deprecated in favor of the App Engine GCS client. Have you considered using a query? Guess-and-check is not a scalable way to find out of an entity exists in a data store. A query can be created to retrieve entities from the datastore that meet a specified set of

I had created web application and deploy it in Google App Engine after I created table(entity) in Google App Engine datastore. My doubt is it possible to download the entity/database? ryan to enable remote_api , add this to your web.xml : <servlet> <servlet-name>remote-api</servlet-name> <servlet-class>com.google.apphosting.utils.remoteapi.RemoteApiServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>remote-api</servlet-name> <url-pattern>/remote_api</url-pattern> </servlet-mapping> details in this thread: http://groups.google.com/group/google-appengine/browse_thread/thread

I've been reading about the remote_api and the bulkloader.yaml configuration file for doing bulk uploads of Google App Engine, but all I really want to do is replace my live datastore on the cloud with the contents of my local datastore. From what I've read, it would seem that I have to first somehow convert my dev_appserver.datastore file into csv or xml, and then apply all the fancy transforms of bulkloader.yaml, which seems like a lot of unnecessary work. Anyone know if there's an easier way? Thanks! It might work to run download_data against localhost and then upload_data , using that dump