The Datastore physically lives on Google's servers. It is spread across multiple servers to provide redundancy and performance. One of the advantages of using GAE is that developer can leverage Google's scalability. The DataStore is developed over Google's BigTable, that hosts many internal and external Google's Services.
The Datastore is a non-relational database. It means unlike traditional databases, developers don't build normalized tables then JOIN them for results. Instead , the DataStore is optimized for Read Speed. The Join Command is not supported. For this reason, the developer need to architect the database as they would for a high volume reporting database, meaning more cloumns and fewer tables.
Many common datatypes are supported in the DataStore including Sting, Int, Float and DateTime. In addition, there is a Key ( system assigned unique row id), phone number and postal address types.
