Databases Reference
In-Depth Information
The APEX Schema
A common misconception about APEX is that it's an extra piece of software that you need to install. In fact, APEX
is a framework that is stored in a schema in the database. At a very high level, each time you request a page,
APEX queries tables in its schema and executes many invocations of the
HTP.P
procedure to produce the HTML
that is sent to the browser.
Each time you create an object in APEX, it's stored in a table in the APEX schema. For example, when you create
a page item, it's stored in the
APEX_040201.WWV_FLOW_STEP_ITEMS
table.
■
As mentioned in Chapter 1, APEX was originally called
FLOWS,
and pages were originally called
STEPS
,
which is why some of the table names contain these references.
Note
Storing code in the database has advantages and disadvantages. An advantage is that you can query the database
to quickly find what you're looking for in an organized fashion. For example, you can easily search through all your
reports for a certain table or column reference. A disadvantage is that it's harder to search through all the objects in an
APEX application at the same time. Searching through an entire application is easier in file-based web applications
because you can do a simple text search.
APEX Views
There are several ways to access the data from the APEX views. This section discusses how to use these views to search
in the APEX development environment.
To access the APEX views in the development environment, go to Utilities
➤
Application Express Views. If you're
new to APEX, we recommend that you change the default view mode to View Report, which provides a detailed
description of each of the reports (see Figure
13-6
).
Figure 13-6.
APEX views
