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Oracle Tips by Burleson |
Shared
Components
There is an icon on the Application Home page to
access shared components. Shared Components are used by many pages in
an application. In some cases, using the publish and subscribe
feature of HTML DB, these shared components can actually be used by
other applications.
Logic: Application
Level Components
Most documentation of Shared Components will not
mention Application Level Components.
That is because, technically, they are not defined in HTML DB as a
shared component. However, an application level component can be used
anywhere within the application. Application Level Components consist
of those described in Table 6.5.
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COMPONENT |
DESCRIPTION |
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Application Items |
Application Level Items are similar to hidden
page level items. They have session state and are not visible
page components. One difference is they are not named with the
page prefix (P100_). Instead, they will be named with the
application prefix F102 for app id 102, or another prefix such as
G_ can be chosen. This has been used to indicate Global. |
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Application Processes |
These are globally defined processes that can
execute for every page in the application. It could be handy for
inserting a record into a table to indicate a page is being
viewed. Another great use for an Application Process is the
ability to define a process here and call it on the appropriate
pages by creating an On Demand process on an application page. |
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Application Computations |
An Application Computation would be setup if
there is a computation the developer wants to execute for every
page in the application or if they simply wanted it to execute
when the user creates a new session, which is when the user first
accesses an application page. The On New Instance computation
point is the one that executes when the user first accesses the
application and is commonly used to read browser cookies. |
Table 6.5:
Application level components
Web Services
The building of web services is covered later in
this book in the section on Creating Other Components with HTML DB.
Build Option
Using build options can disable certain
functionality. This is done by creating a build option and setting
the page component attribute called build option. Figure 6.8 depicts
that a build option named Version 1.1 has been created. It will be
turned on, and at a later time, set to INCLUDE when the new features
are ready for the public. Another use for this is if there are
problems discovered with the new features after the application is in
production, the developer can simply change the build option back to
EXCLUDE and HTML DB will not render the new features. If used
cautiously, this feature could be used to back-out changes in the
middle of the day.
Security
Security will be covered in detail later in this
book in the chapter on HTML DB Administration II.
Navigation
The components responsible for HTML DB navigation
are covered in detail in a later chapter in this book.
The above book excerpt is from:
Easy HTML-DB
Oracle Application Express
Create Dynamic
Web Pages with OAE
ISBN 0-9761573-1-4
Michael Cunningham & Kent
Crotty
http://www.rampant-books.com/book_2005_2_html_db.htm
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