Understanding Facebook's FQL Internally: A Comprehensive Guide

Facebook FQL, or Facebook Query Language, is a powerful tool that enables developers to access user data on Facebook using a SQL-style interface. This makes it an alternative to the Graph API, potentially simplifying the process significantly. In this article, we will delve into how FQL works internally and how it can be leveraged to retrieve workplace information of a user.

What is FQL?

FQL is a specialized query language designed by Facebook to interact with its internal database tables. It provides a way to retrieve and manipulate Facebook data using SQL-like syntax, making it easier for developers to integrate with the platform without having to dive into the complexities of the Graph API.

Retrieving User Work Information with FQL

One of the common use cases for FQL is to retrieve a user's workplace information. When you use the Graph API to get a user's information, the work information is included as part of the user object, typically as a list of employment histories. Each item in this list includes details about the employer, location, and possibly other details.

However, if you need more detailed information about the employer, you can use FQL to query for specific employer pages using the ID of the employer node. This can provide you with additional details, such as the official page of the employer, which is not always available through the Graph API.

Internal Structure and Implementation

When it comes to understanding how FQL works internally, it's important to note that the APIs available to external developers are not the same ones used by Facebook's internal systems. The internal implementation is likely a mix of PHP code, possibly enhanced by cache systems like Memcache and database systems like MySQL. This means that FQL queries are parsed in PHP, and various database and cache operations are performed to retrieve the required data.

Historical Context

There was a historical example of an FQL parser available in PHP, dating back to circa 2008, in Facebook's open platform repository. This implementation provides insight into the historical approach to FQL and how it has evolved over time.

Further Reading

If you are interested in learning more about the anatomy of Facebook and the workings of both the Graph API and FQL, I recommend checking out my tech blog. The articles there explain both APIs and provide basic examples of FQL queries, complete with screen shots to illustrate the process. You can find these resources here:

Additionally, if you have any more questions, feel free to connect with me, Aachri Tyagi, on LinkedIn for further discussions and assistance.

Connect with me: Aachri Tyagi on LinkedIn