How Do I Use Form Fields in a List of Values (LOV)

Introduction
In Oracle APEX, form fields can be used to dynamically populate Lists of Values (LOVs), enabling users to select values that are relevant and context-specific. By linking page items as parameters within LOV queries, you can create responsive dropdowns that change based on user input or other form fields. This makes your application more interactive and user-friendly by displaying only applicable options.

How Do I Use Form Fields in a List of Values (LOV)
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In Oracle APEX, you can use form fields (page items) to dynamically filter and populate Lists of Values (LOVs) based on user input. This technique helps create responsive and context-sensitive dropdowns that improve user experience and data accuracy.

Step 1: Create Page Items
Identify or create the form fields (page items) you want to use as filters in your LOV. For example, you might have a department select list :P1_DEPARTMENT that will control the employee LOV.

Step 2: Write the LOV SQL Query Using Bind Variables
In the LOV definition, write an SQL query that references the form fields as bind variables. For example:

SELECT employee_name, employee_id
FROM employees
WHERE department_id = :P1_DEPARTMENT
ORDER BY employee_name

Here, :P1_DEPARTMENT is the page item whose value dynamically filters the employees shown in the LOV.

Step 3: Set Up the LOV for the Target Item
Assign this LOV query to the page item (such as a select list) that will display the filtered values, for example :P1_EMPLOYEE.

Step 4: Configure Cascading LOV Parent Items
In Page Designer, set the Cascading LOV Parent Item property of the target item (P1_EMPLOYEE) to the controlling page item (P1_DEPARTMENT). This tells APEX that when the parent value changes, the child LOV should refresh.

Step 5: Enable AJAX Refresh
Make sure the target LOV page item has Cascading LOV Parent Item set and that Page Items to Submit include the controlling item(s) if necessary. This enables APEX to submit the controlling item’s value when refreshing the LOV dynamically without a full page reload.

Step 6: Test Your LOV
Run the page and change the controlling form field (P1_DEPARTMENT). The LOV on the dependent item (P1_EMPLOYEE) should update immediately, showing only values that match the selected department.

Best Practices

• Always use bind variables (:P1_ITEM) in your LOV queries to avoid SQL injection and improve performance.

• Set appropriate Cascading LOV Parent Item properties to enable dynamic refreshes.

• Include parent items in Page Items to Submit if you use dynamic actions or custom PL/SQL.

• Test the LOV behavior across all expected input scenarios to ensure it updates correctly.

Using form fields in LOVs is an effective way to build interactive and user-friendly forms in Oracle APEX that respond dynamically to user selections.

Form fields can be used to dynamically populate dropdown lists (LOVs) in Oracle APEX.

Example: Creating a Cascading Select List
When a value is selected in P1_DEPARTMENT, the P1_EMPLOYEE dropdown will show only employees from that specific department.

1. Create a Select List for P1_DEPARTMENT with this query:

SELECT department_name, department_id  
FROM departments  
ORDER BY department_name;

2. Create a Select List for P1_EMPLOYEE using:

SELECT emp_name, emp_id  
FROM employees  
WHERE department_id = :P1_DEPARTMENT  
ORDER BY emp_name;

3. In Page Designer, set the Cascading LOV Parent property of P1_EMPLOYEE to P1_DEPARTMENT.

4. Enable AJAX Refresh for P1_EMPLOYEE so the employee list updates dynamically whenever the department selection change.

Conclusion

Using form fields in LOVs is a powerful way to customize user selections and streamline data entry in Oracle APEX applications. By leveraging dynamic queries and cascading LOVs, you can ensure that dropdown lists remain relevant to the user’s current context, improving both usability and data accuracy. Implementing this technique helps build smarter, more responsive forms.