Hotsos Symposium Speaker – Toon Koppelaars

Mr. Koppelaars is a prior Hotsos Symposium presenter.


Toon KoppelaarsToon Koppelaars is a long-time Oracle technology user, having used the Oracle database and tools software since 1987 (Oracle version 4). During this time, he has been involved in both application development (terminal/host in the early days, GUI client/server later on, and J2EE nowadays), as well as database administration (including Parallel Server administration, the predecessor of Oracle-RAC).

Toon's special interest areas include: the Oracle optimizer (SQL tuning), technical application architectures (from a performance and maintainability perspective), and the specification and implementation of data integrity rules (aka business rules). He is a frequent speaker at Hotsos Symposia, ODTUG and UKOUG.

Together with Lex de Haan, he has co-authored "Applied Mathematics for Database Professionals" (Apress, June 2007).

In 2007, Mr. Koppelaars decided to go independent and founded his own company RuleGen B.V. (

Presentation Title

1: The Helsinki Declaration: Part 1


2: The Helsinki Declaration: Part 2


The Helsinki Declaration: Part 1: The demise of client/server architecture at the end of last century, gave way to lots of new approaches to build, mainly web, applications. A common factor of all new approaches has been to move logic out of the DBMS and put everything in middle tier servers. This of course is absolutely wrong. In this session we will show that code running outside the DBMS a) has serious scalability issues, and b) will need to be completely rewritten every 2-3 years. This ugly state of affairs can be prevented by adopting a database-centric approach to web application development. This approach, which has been presented several times yearly since 2003, was declared to be the only right one, when presented last year in Helsinki in front of a Finnish Oracle developers and DBA audience (hence the title).

The Helsinki Declaration: Part2: Adopting a database-centric development approach will, when done right, prevent the common performance issues that midtier-centric applications are known to suffer from. Window-on-Data applications (that query and transact data and are founded on a sound relational database design) will perform and scale an order of a magnitude better when all "business logic" is implemented inside the DBMS using PL/SQL and SQL. To prevent PL/SQL spaghetti, one must implement a layered architecture inside the DBMS. We will introduce you to such architecture (somewhat mimicing the MVC design pattern commonly deployed in mid-tier centric applications to prevent the same) and demonstrate its implementation by building a simple web-application during this presentation.

Presentation Materials

Presentation materials are available online to attendees only. All parts of Toon's materials may be found on the Hotsos portal. Attendees may use their portal ids to log in to retreive the materials.


The speaker schedules can be found at the following links: