Oracle Pro Tips, Trends & Technology eXTRA Pinnacle Publishing http://www.dsi-enews.net/trk/enews.asp?id=100071201&rc=900005 Issue 3.5 April 17, 2002 TABLE OF CONTENTS 1) Pop Quiz (answer at the end) 2) Books 3) Java Series: Introduction to OC4J 4) Industry News 5) Answer to the Pop Quiz --------------------------------------------------------- 1) POP QUIZ (answer at the end) --------------------------------------------------------- What is an undo tablespace? --------------------------------------------------------- 2) BOOKS --------------------------------------------------------- Osborne has published a book on Oracle9i features. According to their overview, this book discusses Oracle9i managed datafiles, resumable space management, XML development kits, and other features. Find out more at the following site: http://www.dsi-enews.net/trk/enews.asp?id=100071204&rc=900005. --------------------------------------------------------- 3) JAVA SERIES: INTRODUCTION TO OC4J --------------------------------------------------------- The following article is contributed by my colleague, Jim Skehill (mailto:jskehill@procaseconsulting.com), who has years of experience in Java application design and development. He graduated from University of Toronto, and his current project is http://www.dsi-enews.net/trk/enews.asp?id=100071205&rc=900005. Enjoy! * * * * Oracle and Java: Not So Strange Bedfellows In this article, I'll take a look at the background and history of Oracle and its support of Java. When the Java programming language was introduced around 1995, it immediately gained widespread popularity. This was due to the enormous interest in the World Wide Web and to Netscape's key decision to bundle Java into its Web browser. Because of this, Java became the natural choice for Web-based programming. Since then, Java has grown to become the pre-eminent language for software development of both client and server applications. Oracle, while always a dominant force in the database market, was never happy to remain there. It wanted to expand its database product offering into a full-fledged development platform. To this end, Oracle introduced PL/SQL, extending SQL into a procedural programming language. That was in release 7, and, since then, PL/SQL has been the main language of development on the Oracle platform. But, when considering what to put into its 8i release, Oracle saw it as important to support Java as well. By that time, Java had attained critical mass -- that is, it was a widely-known language with a large collection of class libraries and development tools written for it. Any development platform, to be taken seriously, had to support it. Sun had already published J2EE, which was basically a prescribed architecture for Java server-side development: for example, standards for database access, implementing business rules, accessing system resources, etc. Oracle decided to take the plunge and support J2EE. In other words, Oracle 8i would be a full-fledged Java application server. Oracle's initial attempts were ambitious but less than successful. They were ambitious because Oracle decided to implement the J2EE support both outside AND inside the database. (A Java class inside the database ran in the same process space as the database server, making for very fast database access). They were less than successful because the level of support for J2EE, which is, in fact, a collection of APIs that are constantly being updated, quickly fell behind and even varied depending on whether you decided to run outside or inside the database. As a result, Oracle's J2EE support had a real patchwork look-and-feel, and the developers stayed away in droves. Oracle CEO Larry Ellison responded to this failure in typical dramatic fashion. He decided to abandon the existing application server and license an application server called Orion developed by a small Swedish company called IronFlare. Oracle renamed Orion "Oracle Containers for J2EE" or OC4J, and it's now the centerpiece of their Java application server. Orion/OC4J is quite a remarkable product. It's very small, easy to install, and easy to configure. It's also very up to date in its support of the latest J2EE standards. In fact, it's everything that Oracle's previous application server wasn't. In my next column, I'll take a closer look at OC4J. --------------------------------------------------------- 4) INDUSTRY NEWS --------------------------------------------------------- In an article published on thestree.com, the author talked about Oracle's ERP initiatives and how they're not meeting the initial targets of Oracle. According to the article, Oracle's licensing revenue for its ERP product declined by 25 percent for the past two quarters. Aside from the economic downturn, the article tried to examine some of the factors contributing to the decline. This included software bugs and the perception that its software was not the "best of breed." The article then examined attempts made by Oracle to improve the situation. Find out more about this article at the following link: http://www.dsi-enews.net/trk/enews.asp?id=100071206&rc=900005. --------------------------------------------------------- 5) ANSWER TO THE POP QUIZ --------------------------------------------------------- Prior to Oracle9i, rollback segments are created to support transaction processing. In particular, they're used to store the before-image of changed records. Oracle9i provides "automatic undo management" (AUD), which provides another method of storing undo records, by using undo tablespaces. With AUD, you no longer need to perform micro-management of the rollback segments -- that is, creating a rollback tablespace, creating rollback segments, taking them online, etc. In summary, AUD offers the following advantages: -- You only need to specify the undo tablespace, and Oracle will take care of creating and activating the rollback segments automatically. -- You can specify how much history to keep -- for example, retain three days of undo data before being overwritten. - You can issue flashback queries, which allow you to view data values before the commit. If you're interested, I'll provide more examples next time. For details, please refer to the Oracle9i Database Administrator's Guide. --------------------------------------------------------- Well, that's it for this week. I welcome your feedback, input, tips, suggestions, Web sites, and other Oracle- related news. If you send me something, please let me know whether I can use your name with your comments. I apologize in advance if I don't respond personally to each of your questions or suggestions, but I'll get to as many as I can in the eNewsletter if not personally. Garry Chan, Editor Database Architect mailto:GChan@ProcaseConsulting.com This eNewsletter is brought to you compliments of Pinnacle Publishing, Inc. Copyright(c) 2002 http://www.dsi-enews.net/trk/enews.asp?id=100071210&rc=900005 All rights reserved.