What's a namespace used for in the App Engine datastore?

Question

In the development admin console, when I look at my data, it says "Select different namespace".

What are namespaces for and how should I use them?

Answer 1

Namespaces allow you to implement segregation of data for multi-tenant applications. The official documentation links to some sample projects to give you an idea how it might be used.

Answer 2

Namespaces is used in google app engine to create Multitenant Applications. In Multitenent applications single instance of the application runs on a server, serving multiple client organizations (tenants). With this, an application can be designed to virtually partition its data and configuration (business logic), and each client organization works with a customized virtual application instance..you can easily partition data across tenants simply by specifying a unique namespace string for each tenant.

Other Uses of namespace:

1. Compartmentalizing user information
2. Separating admin data from application data
3. Creating separate datastore instances for testing and production
4. Running multiple apps on a single app engine instance

For More information visit the below links:

http://www.javacodegeeks.com/2011/12/multitenancy-in-google-appengine-gae.html
https://developers.google.com/appengine/docs/java/multitenancy/
http://java.dzone.com/articles/multitenancy-google-appengine

http://www.sitepoint.com/multitenancy-and-google-app-engine-gae-java/