The document provides a detailed guide on how to reference and set form parameters in PL/SQL using bind variable syntax and outlining the use of the add_parameter procedure. It emphasizes the importance of checking for existing parameter lists to avoid errors and explains the process of creating parameters and implementing them within forms. Additionally, it illustrates how to utilize the form_success function for error handling during form operations.

1. PART 36- PARAMETER
FORM_SUCCESS
Dr. Girija Narasimhan

2. Referencing Parameters
In PL/SQL, you can reference and set the values of form parameters using
bind variable syntax.
To reference a parameter: Preface the parameter name with the reserved
word PARAMETER, as shown in the following examples:
:PARAMETER.parameter_name := ‘p_deptno';
Or
:dept.deptno:= :PARAMETER.p_deptno;
Dr. Girija Narasimhan

3. Alternative method
Object Navigator parameters  create  new parameter(parameter2)
Property Palette  Name change as ‘p_deptno’
Parameter data type
-> number
Maximum length -> 2
Parameter initial value
-> 10
Dr. Girija Narasimhan

4. Dr. Girija Narasimhan
PROCEDURE ADD_PARAMETER
(list VARCHAR2,
key VARCHAR2,
paramtype NUMBER,
value VARCHAR2);
ADD_PARAMETER Restrictions
A parameter list can consist of 0 (zero) or more parameters.
You cannot create a parameter list if one already exists; to do so will cause an
error. To avoid this error, use ID_NULL to check to see if a parameter list already
exists before creating one. If a parameter list already exists, delete it with
DESTROY_PARAMETER_LIST before creating a new list.
You cannot add a parameter of type DATA_PARAMETER if the parameter list is
being passed to another form

5. Dr. Girija Narasimhan
list or name Specifies the parameter list to which the parameter is assigned. The
actual parameter can be either a parameter list ID of type PARAMLIST, or the
VARCHAR2 name of the parameter list.
key The name of the parameter. The data type of the key is VARCHAR2.
paramtype Specifies one of the following two types: TEXT_PARAMETER A
VARCHAR2 string literal.
DATA_PARAMETER A VARCHAR2 string specifying the name of a record group
defined in the current form. When Oracle Forms passes a data parameter to
Reports or Graphics, the data in the specified record group can substitute for a
query that Reports or Graphics would ordinarily execute to run the report or
display.
value The actual value you intend to pass to the called module. If you are passing
a text parameter, the maximum length is 64K characters. Data type of the value is
VARCHAR2.

6. Dr. Girija Narasimhan
Searches the list of parameter lists and returns a parameter list ID when it finds
a valid parameter list with the given name.
You must define an variable of type PARAMLIST to accept the return value.
This function is similar to the FIND_ functions available for other objects.
GET_PARAMETER_LIST Built-in
FUNCTION GET_PARAMETER_LIST(name VARCHAR2);

7. Use FORM_SUCCESS to test the outcome of a built-in to determine further
processing within any trigger.
To get the correct results, you must perform the test immediately after the
action executes.
That is, another action should not occur prior to the test. "Another action"
includes both built-ins and PL/SQL assignment statements.
If another action occurs, FORM_SUCCESS may not reflect the status of the
built-in you are testing, but of the other, more recently executed action.
Dr. Girija Narasimhan
FORM_SUCCESS

8. Step 1: create parameter

9. Step 2: create data block “dept”
Step 3: quit button write “exit_form”
Step 4: when_new_form_instance –write ‘execute_query’

10. Step 5: in the dept data block property palette  where clause
deptno=:parameter.p_deptno

11. Step 6: create emp data block as tabular format
Step 7: create control block create item push button as “show_me_department_info”

12. Step 8: In show_me_department_info push button when_button_pressed trigger 
write following coding given in slide 13, slide 14

13. DECLARE
p_id paramList; -- This is a variable that contains id of the parameter list
p_name VARCHAR2(20); -- A variable that keeps your parameter name
BEGIN
p_name := 'myparameter';
p_id := GET_PARAMETER_LIST('p_name'); -- find it if exists.
IF NOT ID_NULL (p_id) THEN
-- If exit then destroy it.
DESTROY_PARAMETER_LIST(p_id);
END IF;
--Now create a parameter list and add your p_deptno parameter.
p_id := CREATE_PARAMETER_LIST('p_name');
ADD_PARAMETER(p_id,'P_DEPTNO',TEXT_PARAMETER,to_char(:deptno));

14. --- You can call the called program either by default or specific like c:.
OPEN_FORM('e:tutorialdept.fmx',ACTIVATE,SESSION,p_id);
-- Error messages in case the called program was not able
-- to open called program.
IF NOT FORM_SUCCESS THEN
MESSAGE('ERROR: Unable to open the DEPARTMENT form.');
RAISE FORM_TRIGGER_FAILURE;
END IF;
EXCEPTION
WHEN others THEN
MESSAGE ('Error: unable to create parameter list…');
RAISE FORM_TRIGGER_FAILURE;
END;

15. Step 9 : compile dept.fmb and emp.fmb
Step 10: Run emp.fmb

16. Step 11: instead of dept.fmx give dep.fmx and check whether form_success and
exceptions are working

17. Reference:
everythingOracle.bizhat.com chapter 22