Types Of Triggers In Oracle Reports

What types of triggers are there in oracle report ?

      There are eight Triggers available, among them five triggers consider as global Oracle Report triggers and these trigger are used initializing parameter values, Validate Parameter values and Dynamic query execution

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