Persisting data in Datastore

Even if users can log in and submit a note, our application isn't very useful until notes are stored somewhere. Google Cloud Datastore is the perfect place to store our notes. As part of App Engine's infrastructure, it takes care of data distribution and replication, so all we have to do is define store and retrieve our entities using the Python NDB (Next DB) Datastore API.

Note

There are currently two APIs available in the Python runtime to interact with Datastore: the DB Datastore API, also known as ext.db, and the NDB Datastore API. Even if both the APIs store exactly the same data in Datastore, in this book, we will only use NDB; it is more recent, provides more features, and its API is slightly more robust.

An entity has one or more properties that in turn have a name and a type; each entity has a unique key that identifies it, and instead of storing different data in different tables as in a relational database, every entity in Datastore is categorized...