The SitePoint PHP blog has a post today about combining PHP and Neo4j, a popular graph database, and create a simple application.

In this post, we’ll be learning about Neo4j, the leading graph database, and ways to use it with PHP. In a followup post, we’ll be building a proper graph application powered by Silex. [...] For the newcomers, here is a short introduction to graph databases and Neo4j, apart from the theoretical glance we threw at it last year.

For those not familiar with some of the concepts behind graph databases, they start with a quick introduction. They illustrate the concept of relationships with a few helpful images. They also cover the basics of Cypher, the language used in Neo4j database queries. They then show how to get the Neoxygen components installed to talk with the Neo4j database (via an HTTP API) and configuring a basic connection. The remainder of the post shows how to insert data into the database, including relationships, and pulling that information back out via PHP.