Google AppEngine Database

Question

I read a little about Google AppEngine, which provides application hosting. I tried this as I think it looks pretty interesting, but I'm a bit concerned about the database part.

Say I'm developing my Java application locally. I don’t want to deploy to Google every time I make changes to the code, so I set up a small Servlet container on my development machine for easy testing. With AppEngine, you store things using your data warehouse API, which basically allows you to model your data using Java objects - which is nice.

However, it seems that this data is embedded in the application code itself (inside the .war, which is deployed to Google). Can I just use their api data store locally? How will it be stored on my local machine? This is all handled by them, so I just need to worry about using the data warehouse API and when it is deployed to Google, the data will be stored differently than how it is stored on my local machine?

I'm a little confused because I'm used to the fact that some of the data is aligned from my application code.

I hope I'm clear enough. Thanks.

Answer 1

The development of a datastore and the production of a data warehouse are two different and separated things:

A development data warehouse is a typical file-based data warehouse called local_db.bin , which is simply useful to store your data in a test environment; When you deploy the application, data is not replicated to the production environment.
This type of data warehouse is intended for use with a fairly small number of objects, and its performance has nothing to do with the powerful atrocious data producer based on Big Table .

All you have to do is use the Datastore API, which creates an abstraction layer between your code and the underlying data store; during testing, your data will be stored in a local data warehouse file, during production, the created data will be saved in the Google App Engine data warehouse with all the functions and limitations that this implies.