Starting with release 10g, the scheduling mechanism has considerably evolved from a simple task launcher to a powerful Scheduler. Oracle Scheduler allows complex scheduling that would be otherwise very difficult to program in previous releases. The OS Scheduler is very limited compared with the potential provided by the Oracle Scheduler.

Oracle provides an enriched set of scheduling time expressions that allow the user to define complex time expressions. Even though Oracle Scheduler has greatly simplified the way to schedule tasks, its concepts and syntax are not quite clear at first glance, Oracle is aware of the scheduling complexity, but Enterprise Manager frees the DBA from this complexity, displaying the Scheduler mechanism in a very simple an intuitive way, allowing the DBA to be more productive when defining the different required schedules.

In this chapter, we learned the basic Scheduler concepts, the time expression syntax, and the Scheduler management basics. In the next...