In this chapter, we put into action Cloud SQL, the scalable database service offered by Google Cloud Platform. Cloud SQL is more than a MySQL instance; it is a flexible and scalable relational database server that we can use to store and retrieve data from our App Engine applications as well as from external services and applications.

Even if Cloud Datastore is the go-to solution when we have to deal with lot of data in our highly trafficked web applications, in this chapter, you learned how convenient it can be to have a relational database to store some data without hitting on the limits Datastore imposes to write operations. Being able to access that data from outside App Engine is a big plus and we have seen a simple yet effective use case, which we couldn't have implemented using Datastore.

In the next chapter, we will add new features to our Notes application; we will make the application real time using Channel API to push data from the server to the clients connected.