SQL databases don't necessarily require heavy-weight database servers with expensive database administrators. SQLite3 (http://www.sqlite.org/) is easy to set up: it's just a self-contained library linked into your application, and is a server-less, no-configuration-required SQL database engine. The node-sqlite3 project (https://github.com/developmentsed/node-sqlite3) interfaces sqlite3 into Node.
Installation is very simple if you have npm installed:
$ npm install sqlite3
Installing this module requires having the
sqlite3 library installed on your system, and the npm module which contains native code (in C) that links to the
sqlite3 library. The library is already installed on Mac OS X, and ...