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Oracle Tips by Burleson |
Region Pos 1
Notice in Figure 12.8 that the Region Pos 1 region
is rendered above the text Before Regions Process Point. This is
significant because to use computations or processes to set a page
item in the Region Pos 1 region, execution points of before header or
after header must be used. Trying to set page items in the Region Pos
1 region with any other execution points would fail.
Before Regions Computations and Processes
Keeping an eye on Figure 12.8, notice that the
Template Body 1 region is rendered after the text BeforeRegions
Process Point. Therefore, computations and processes can be used in
the before regions execution point to set page item values in the
Template Body 1 region.
After Regions Computations and Processes
Throughout this book, many regions were created in
the same position as Template Body 1
. This is because this position is
the default location when a new location is created, and most often it
is simply accepted. Actually the default is Template Body 3, but they
are both part of the box body, the #BOX_BODY# substitution string in
page templates.
There will come a time when a developer will
create a region in this location or execution point and try to set
page item values with an After Regions computation or process. This
would be in error, but it happens. What will happen is that when the
web page is refreshed, the page item will then have a value. This is
because when the page is rendered the first time, the session state of
the page item in the Template Body 1 region was set to after the
region was rendered.
However, when the page refreshed, the page item
was populated with the value from session state. This could give a
false indication that the change is working. What really needs to be
done is to either move the computation or process to a before regions
execution point or move the region down to be after the after regions
execution point.
The after regions execution point is used to set
page item values rendered after this execution point. It can
reference any page item that is rendered prior to this execution
point.
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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