Chapter 7. Data Storage and Retrieval

In the previous two chapters, we built a small and somewhat useful application for storing notes, and then made it work on mobile devices. While the application works reasonably well, it doesn't store those notes anywhere for long-term storage, which means the notes are lost when you stop the server. Further, if you run multiple instances of Notes, each instance has its own set of notes; this makes it difficult to scale the application to serve lots of users.

The typical next step in such an application is to introduce a database tier. Databases provide long-term reliable storage, while enabling easy sharing of data between multiple application instances.

In this chapter, we will look at database support in Node.js in order to provide these capabilities:

• The user must see the same set of notes for any Notes instance accessed
• Reliably store notes for long-term retrieval

We'll start with the Notes application code used in the previous chapter...