Databases Reference
In-Depth Information
To see the results of adding the new item, run the application and navigate to the Tickets report (page 200). Click
one of the Edit icons to bring up the single record view (page 210). You should now see the result of the computation
as a number of days. When starting the process of creating a new ticket, the field isn't displayed because the condition
prevents the field from showing.
Processes
If computations are analogous to database functions, then processes are analogous to database procedures. A process
is a container for a unit of logic.
Processes are arguably the most complex part of APEX, because they're the construct used to deal with
data processing in the database as well as references to APIs such as those used to send e-mail and perform any
other business logic required in the application. When dealing with data forms, the APEX wizard creates built-in
processes that manage the reading and writing of data from the form. Those types of built-in processes are called
data-manipulation processes
.
Processes, similar to computations, can occur during both page rendering and page processing. In the Page
Definition screen, the processing locations are identified by the gear icons. Processes support the APEX conditions
feature, which allows processes to be written as individual logic units with conditions determining whether the logic
is needed.
Execution Points
Process execution points are the same as for computations. The most commonly used execution points for processes
are On Submit - After Computations and Validations and On Demand - Run This Process When Requested by AJAX,
because as these points support button-press activities and dynamic actions. The full list is as follows:
•
On New Instance - (New Session)
•
On Load - Before Header
•
On Load - After Header
•
On Load - Before Regions
•
On Load - After Regions
•
On Load - Before Footer
•
On Load - After Footer
•
On Submit - Before Computations and Validations
•
On Submit - After Computations and Validations
•
On Demand - Run This Process When Requested by AJAX
Processes can be defined at the individual page level or at the application level as part of the shared components.
Functionally, page processes and application processes behave the same. The difference is where business logic
is contained. For processes that need to run on all pages, you can define an application process. Also, just as with
regions, you can use Global Pages to define processes that run on every page, but only for page rendering.
