google-cloud-datastore

I'm developing an application on Google App Engine using Maven. When I run the local server I would like to have some data preloaded in the datastore, such as the local user table. The server puts the datastore file under the WEB-INF/appengine-generated of the target directory and it is cleaned before every build. Is there a convenient way to do so? You have a couple of options: a. backup and reload local_db.bin in your build steps b. use the datastore.backing_store system property with: dev_appserver.sh --jvm_flag= -Ddatastore.backing_store=\path\to\local_db.bin 来源： https://stackoverflow.com

I've watched this video from Google I/O 2009: http://www.youtube.com/watch?v=AgaL6NGpkB8 where Brett shows microblogging example. He describes two datastore schemas: first one: class Message(db.Model): sender = db.StringProperty() body = db.TextProperty() receivers = db.StringListProperty() and second one: class Message(db.Model): author = db.StringProperty() message = db.TextProperty() class MessageIndex(db.Model) receivers = db.StringListProperty() And he says that in first example datastore has to serialize/deserialize receivers property every time we query messages by receiver, and in

There is a nice explanation of 1-to-many relationships in datastore here by Rafe Kaplan. I tried to adapt that to a simpler case of User and Venue . So user can go to many restaurants; and I want to print the user email and the restaurants the user went to: class User(db.Model): userEmail = db.StringProperty() class Venue(db.Model): user = db.ReferenceProperty(User, collection_name="venues") venue = db.StringProperty() class OneToMany(webapp.RequestHandler): def get(self): scott = User(userEmail="scott@example.com") scott.put() Venue(user=scott, venue="club1").put() Venue(user=scott, venue=

Is there any way how to set a kind name different from a class name used in my Google App Engine? I am using Java and JDO to access a datastore. There a question about the similar issue in Python. It seems answered. Set a kind name independently of the model name (App Engine datastore) Ooops... It was quite easy to achieve: @PersistenceCapable(table = "person") public class PersonEntity { // ... } 来源： https://stackoverflow.com/questions/7616158/set-an-entity-kind-name-different-from-a-class-name

I am using GAE Python. I have two root entities: class X(ndb.Model): subject = ndb.StringProperty() grade = ndb.StringProperty() class Y(ndb.Model): identifier = ndb.StringProperty() name = ndb.StringProperty() school = ndb.StringProperty() year = ndb.StringProperty() result = ndb.StructuredProperty(X, repeated=True) Since google stores our data across several data centers, we might not get the most recent data when we do a query as shown below(in case some changes have been "put"): def post(self): identifier = self.request.get('identifier') name = self.request.get('name') school = self

When writing the endpoints in java, for finding items by their keys, should I use the Id or the webSafeString of the key? In what situations does this matter? It's up to you. Do the entities have parents? Then you probably want to use the urlsafe representation as a single string will contain the full path to the entity. If you used an ID instead - you would somehow need to manually include the IDs of all parents up to the root. No parents & IDs are numeric / alphanumeric? Then just use the IDs as they look cleaner (again, this is not a rule and is completely up to you). No parents but IDs

I am trying to understand the 1-to-many relationships in datastore; but I fail to understand how query and update the record of a user when the model includes ReferenceProperty . Say I have this model: class User(db.Model): userEmail = db.StringProperty() userScore = db.IntegerProperty(default=0) class Comment(db.Model): user = db.ReferenceProperty(User, collection_name="comments") comment = db.StringProperty() class Venue(db.Model): user = db.ReferenceProperty(User, collection_name="venues") venue = db.StringProperty() If I understand correctly, the same user, uniquely identified by userEmail

In GAE, when using Objectify, can you query a HashMap? If so how would would you write it? ofy().load().type(MyClass.class).filter("hashMapfieldName", "keyQueryinggFor").list(); Does not seem to work where the hashMapfieldName is a HashMap<String, String> . I am looking to find entities where hashMapfieldName contains a certain key. Just like embedded classes, Objectify converts Map<String, String> to the low-level EmbeddedEntity object, which is not indexible. However, if you @Index your Map field (or embedded class field), Objectify will create a synthetic index that lets you query anyways.