Building Social Web Applications

Chapter 11. Modeling Data and Relationships

Turning things, people, and relationships from ideas and sketches into social objects on the Web means creating URLs that people can use to access them. You need to represent these social objects in a data model, mapping the people, for example, to a series of user ID fields, and then linking these user IDs to the videos they have uploaded and the comments they have made. Behind the URLs is a database that holds the relationships between all of these items.

People, location, and group membership can seem simple to model at first glance. A person has a name and a login ID, probably a profile, and an avatar image. However, locations can change when you factor in time as a variable. Do you keep the current location only? The answer will depend on the type of application you are developing.

Anyone coming to your application will need to use a URL to access the social interactions and content on your site. If you create these URLs without any thought, you can end up with a site structure that is hard to understand. Good URL design is a key starting point for good data modeling.

Designing URLs

In the late 1990s, the rush of people and companies to get online meant that well-meaning guidelines were largely ignored and people created URLs any which way they wanted. Tim Berners-Lee wrote some good guidelines early on for how to manage URLs (see http://www.w3.org/DesignIssues/Axioms.html and http://www.w3.org/Provider/Style/URI), but it wasn’t until ...