Web Development with Node and Express, 2nd Edition

Chapter 13. Persistence

All but the simplest websites and web applications are going to require persistence of some kind; that is, some way to store data that’s more permanent than volatile memory so that your data will survive server crashes, power outages, upgrades, and relocations. In this chapter, we’ll be discussing the options available for persistence and demonstrating both document databases and relational databases. Before we jump in to databases, however, we’ll start with the most basic form of persistence: filesystem persistence.

Filesystem Persistence

One way to achieve persistence is to simply save data to so-called flat files (flat because there’s no inherent structure in a file; it’s just a sequence of bytes). Node makes filesystem persistence possible through the fs (filesystem) module.

Filesystem persistence has some drawbacks. In particular, it doesn’t scale well. The minute you need more than one server to meet traffic demands, you will run into problems with filesystem persistence, unless all of your servers have access to a shared filesystem. Also, because flat files have no inherent structure, the burden of locating, sorting, and filtering data will be on your application. For these reasons, you should favor databases over filesystems for storing data. The one exception is storing binary files, such as images, audio files, or videos. While many databases can handle this type of data, they rarely do so more efficiently than a filesystem (though information ...