What
types of triggers are there in oracle report ?
Following
Order of Oracle Triggers Firing sequence
1.Before Parameter
Form
2.After Parameter Form
3.Before Report
4.Between Pages
5.After Report
1. Before Parameter Form: Fires before the
Runtime Parameter Form is displayed. From this trigger, you can access and
change the values of parameters, PL/SQL global variables, and report-level
columns. If the Runtime Parameter Form is suppressed, this trigger still fires.
Consequently, you can use this trigger for validation of command line
parameters.
2. After Parameter Form: Fires after the
Runtime Parameter Form is displayed. From this trigger, you can access
parameters and check their values. This trigger can also be used to change
parameter values or, if an error occurs, return to the Runtime Parameter Form.
Columns from the data model are not accessible from this trigger. If the
Runtime Parameter Form is suppressed, the After Parameter Form trigger still
fires. Consequently, you can use this trigger for validation of command line
parameters or other data.
3. Before Report: Fires before the
report is executed but after queries are parsed
4. Between Pages: Fires before each
page of the report is formatted, except the very first page. This trigger
can be used for customized page formatting. In the Previewer, this trigger only
fires the first time that you go to page. If you subsequently return to the
page, the trigger does not fire again.
5. After Report: Fires after you exit the Previewed, or after
report output is sent to a specified destination, such as a file, a printer, or
an Oracle Office userid. This trigger can be used to clean up any initial
processing that was done, such as deleting tables. Note, however, that this
trigger always fires, whether or not your report completed successfully.
Following
three general triggers not consider as main triggers:
1.Validation Triggers
2.Format Triggers
3.Action Triggers
1.
Validation Triggers: Validation trigger
are PL/SQL functions that are executed when parameter values are specified on
the command line and when you accept the Runtime Parameter Form. (Notice that this means each
validation trigger may fire twice when you execute the report) Validation
trigger are also used to validate the Initial Value property of the parameter.
The function must return a boolean value.
2.
Format Triggers: This trigger are PL/SQL functions executed before the
object is formatted. The trigger can be used to dynamically change the
formatting attributes of the object. The function must return a Boolean
value (TRUE or FALSE). Depending on whether the function returns TRUE or
FALSE, the current instance of the object is included or excluded from the
report output. You can access format triggers from the Object Navigator,
the Property Palette, or the PL/SQL Editor.
Definition Level: layout object
On Failure: Excludes the current
instance of the object from the output.
Format trigger example (highlighting a value)
/* suppose that you are building a banking
report and would like it to indicate if a customer is overdrawn. To do so, you
give the repeating frame around the customer information a format trigger that
causes it to have a border only if a customer's account balance is less than 0
(or the required minimum balance). */
function my_formtrig return BOOLEAN
is begin
if: bal < 0 then
srw.attr.mask := SRW.BORDERWIDTH_ATTR;
srw.attr.borderwidth
:= 1;
srw.set_attr (0,
srw.attr);
end if;
return (true);
end;
3. Action Triggers:
Action triggers are
PL/SQL procedures executed when a button is selected in the Runtime Previewer.
The trigger can be used to dynamically call another report (drill down) or
execute any other PL/SQL. You can access action triggers from the Object
Navigator, the Property Palette (PL/SQL Trigger property), or the PL/SQL
Editor.
Definition Level: button
