Relational Databases - No Longer the Key to the Castle
It has been 40 years since Codd published his "A relational model of data for large shared data banks" - ushering in the era of relational databases. Since then, the industry has built applications around relational data at the core. RDB's have become the core asset of many companies.
However, this is changing because of the web. A case could be made that the most valuable database in the world is Google's index of the web - certainly not a relational database. The web's core is built around documents and document linking. Content and new architectures for databases like Big Table and Hadoop are now replacing RDB's as the core of applications.
This has some implications for the Java community and the traditional focus on building RDB-driven applications. The focus of Java middleware has been on EJB's and JDBC and Hibernate and create applications on top of these API's. This has led many Java shops to fall behind what is happening on the consumer web. While the traditional transactional RDB driven apps are fine, they are not as useful as they should be.
eXo offers a platform that fully integrates with traditional Java middleware like Tomcat, JBoss, Spring, WebSphere and others. However, it focuses on content, collaboration, social and knowledge. All of the services offered by eXo focus around the new types of data. At the core is an open content store based on the Java Content Repository specification with open interfaces like WebDAV, CMIS, and back end integration with storage services like S3.
This infrastructure allows Java shops to instantly leap forward to an integrated architecture that encompasses the new data types of the Web.
When people ask us how we have so much functionality in our platform, one of the key reasons is that we did not take the typical Java approach of trying to force everything into a traditional RDB view of the world. We matched the architecture to that of the web - around content, collaboration, social and knowledge.