Database Reference
In-Depth Information
jects, target the same user community, or use the same method for authenticating users.
As you build an application, you add new pages and build out those pages with re-
gions and items.
Figure 2-2
shows the hierarchy of the different types of objects.
Figure 2-2.
General application hierarchy
Applications
are basically groups of pages that perform a task (or set of tasks) re-
lated to a business function. During the course of this topic you'll build one application
in a single workspace, but it's important to know that in a typical development environ-
ment, you'll probably be working on many applications across several workspaces.
Pages
are the basic building blocks of applications and contain both the user inter-
face components and the programming logic that processes the user's input. We cover
the rendering of the UI versus the processing of user input later, but for now consider a
page roughly equivalent to a screen in desktop UI lingo.
Regions
are UI items that serve as content containers. You can have any number of
regions on a page, and in APEX 4, regions can be nested in other regions. This gives
you the opportunity to create things like dashboards where you might nest a data report
region and a graph region in a single parent HTML region.
Items
are the HTML form elements that are used to present the UI to the user. These
include things such as buttons, select lists, text fields, check boxes, radio groups, and
so on. There are two categories of items: page-level items and application-level items.
The difference is that the latter are defined at the application level and aren't rendered
directly on the page. You can think of these as global variables. Page-level items are
defined on a specific page and assigned to a region in order to control where and how
they display to the user.
