Apex: Validation on two dependent page items

Question

Apex 4.2
I have a  form with two separate regions that each have text fields / select list on them. I need to validate one field againt another.
**Region 1
- P10_REQUESTOR
- Select List
- LOV defenition:
SELECT first_name
FROM PERSONS
ORDER BY firs_name
I.e. you can select a first name from the select list
**Region 2
- P11_NAME
- Text Field
A regular text field to  type in the first name of a person
**Logic:
When a user navigates to this page, they can either pick a first name from the select list OR if the name is not in the list, they can type in the name in the P11_NAME text field. However, they can not do both. I am having a little trouble writing a validation script to capture these cases.
Case 1: P10_REQUESTOR is null & P11_NAME is not null
Case 2: P10_REQUESTOR is not null & P11_NAME is null
If both items are null then an error message needs to appear stating that one or the other must be filled out
If both items are not null then an error message needs to appear stating that you can only fill out one or the other
I have pseudo coded it and understand the logic but am having trouble on knowing which options to choose when creating the validation. I was thinking its somewhere along the lines of a PL/SQL function with a few IF statments in it.
Any help would be greatly appreciated. Thanks in advance.

Answer 1

Hi NewApexCoder,
your problem is solved in two ways,if i understand you correctly.
You can do a simple javascript on the  NAME i.e you can enable and disable this item_type by putting this snippet into the  Form element attributes
To take care of Case1
OnBlur = "javascript: if (this.value != '') { document.getElementById('P11_NAME').value = 0; document.getElementById( ' P11_NAME').disabled = true; } else {document.getElementById ( 'P11_NAME').disabled = false;}"
OR
2.  In the  Select List Page Item ,By adding an extra  Display Extra Values = YES
                                   Display Null Value  = YES
Null Display Value = '%'    Null Return Value = -1
After which you can set up a validation for an item.
Validations> Page>P10_REQUESTOR>  Then choosing a PLSQL Function Returning Boolean
Validation Code
begin
if P10_REQUESTOR = -1 then
return true;
else
return false;
end;
2.Error Message
"A Request must be selected"
To take care of case 2
Thanks
Benjamin.
www.bkintsiful.blogspot.com