SQL has been around for more than 20 years, and its age has begun to show — especially in the face of other developments. First, the object-oriented programming paradigm, introduced at about the same time as SQL, became mainstream at the beginning of the 1990s. And the Internet has now created a seemingly insatiable demand for structured data and opened new ways of using and creating information. As computers become more powerful, new uses have emerged — for example, analyzing vast amounts of data for uncovering hidden trends, replication over the Internet, storing data in new data formats like video, MP3 and more.
These developments have all placed pressure on SQL to transform and adapt. SQL3 standards have introduced new data types, bridging gaps between text-oriented SQL and object-oriented software. RDBMS vendors have added capabilities to utilize objects within standard relational framework (e.g., Java-stored procedures, ActiveX (OLE) Automation, XML etc.). New object-oriented database systems (OODBS) and object-oriented relational database systems (OORDBMS) have sprouted.
This chapter discusses some major new technologies that relate to SQL. Some of the emerging technologies — for instance EJB (Enterprise Java Beans) or Web services (exposing functionality over the Internet) — would be only briefly touched. Readers interested in using these technologies in conjunction with SQL, are encouraged to read books dedicated to the topic.
We recommend in particular Mastering Enterprise JavaBeans, Second Edition, by Ed Roman, Scott W. Ambler, and Tyler Jewell (Wiley, 2001).