OCA /OCP Oracle Database 11g A ll-in-One Exam Guide- P87:There is an ever increasing demand for staff with IT industry certification. The benefits to employers are significant—they can be certain that staff have a certain level of competence—and the benefits to the individuals, in terms of demand for their services, are equally great. Many employers are now requiring technical staff to have certifications, and many IT purchasers will not buy from firms that do not have certified staff. | OCA OCP Oracle Database 11g All-in-One Exam Guide 816 Figure 22-4 Creating a schedule with Database Control To create a job select the Jobs link. The initial window shown in Figure 22-5 assumes that the job is a PL SQL block. Select the change command type button to nominate your program. The Schedule link lets you tie the job to a precreated schedule rather than defining the schedule within the job. Note that Database Control by default reverses the values for ENABLED and AUTO DROP from the actual defaults. TIP Programs share the same namespace as jobs you cannot have a program with the same name as a job. The same is true for schedules and windows. It is also possible to run a job independently of a schedule by using the RUN_JOB procedure SQL exec savedate Chapter 22 The Scheduler 817 Figure 22-5 Creating a job with Database Control PART III Event-Driven Jobs The event that launches an event-driven job takes the form of a message delivered to a queue. The Oracle Database s Advanced Queuing facility is a means for managing the asynchronous delivery of messages. The queue exists within a table one column of which is a user-defined object that carries the payload of the message the other columns are used by the Advanced Queuing control structures. The flow is that a process or possibly several processes should place messages on the queue. The Scheduler will monitor the queue and depending on the content of messages launch particular jobs. A full treatment of this is beyond the scope of the OCP examinations but an appreciation of how an event can launch a job is required. This is a summary of the steps with examples of the necessary code to implement a job that will run when a file has been delivered 1. Create an abstract data type to define the events create type incoming_t as object event_type number OCA OCP Oracle Database 11g All-in-One Exam Guide 818 2. Create a queue table to store queues that use this object type exec .
