How Do I Apply Access Control in Oracle APEX

Introduction

Applying access control in Oracle APEX is a fundamental aspect of securing applications, ensuring that users can only interact with components and data they are authorized to access. Oracle APEX provides a built-in Application Access Control feature that simplifies role-based access management, allowing developers to define roles, assign them to users, and apply authorization schemes to control access to pages, regions, or buttons. This blog post will guide you through the process of applying access control in Oracle APEX, provide detailed steps for implementation, share best practices, and include a link to the official Oracle APEX documentation for further guidance.

Steps to Apply Access Control in Oracle APEX

1. Understanding Application Access Control
   Oracle APEX’s Application Access Control feature, located in Shared Components, enables role-based access management. It allows you to define roles (e.g., Administrator, Editor, Viewer) and associate them with users, typically through a database table. These roles are then used in authorization schemes to restrict access to application components.

2. Setting Up Application Access Control
   To configure access control:

   • Navigate to Shared Components > Application Access Control in your Oracle APEX application.
   • Click Add Role to define roles such as "Administrator," "Editor," or "Viewer." Assign a unique name and description for each role.
   • Create a table to store user-role mappings, or use the default APEX_ACCESS_CONTROL table. Example table structure:

     CREATE TABLE apex_access_control (
       username VARCHAR2(100),
       access_level VARCHAR2(50),
       CONSTRAINT pk_apex_access_control PRIMARY KEY (username)
     );
     

   • Populate the table with user-role assignments. Example:

     INSERT INTO apex_access_control (username, access_level) VALUES ('JOHN_DOE', 'ADMINISTRATOR');
     INSERT INTO apex_access_control (username, access_level) VALUES ('JANE_SMITH', 'EDITOR');
     

3. Creating Authorization Schemes for Access Control
   Create authorization schemes that leverage the roles defined in Application Access Control:

   • Go to Shared Components > Authorization Schemes.
   • Click Create and define a scheme (e.g., "Admin_Only").
   • Select the scheme type as Exists SQL Query and use a query to check the user’s role. Example:

     SELECT 1
     FROM apex_access_control
     WHERE username = :APP_USER
     AND access_level = 'ADMINISTRATOR';
     

   • Alternatively, use a PL/SQL Function Returning Boolean for more complex logic:

     FUNCTION is_admin (p_username IN VARCHAR2) RETURN BOOLEAN IS
       l_count NUMBER;
     BEGIN
       SELECT COUNT(*) INTO l_count
       FROM apex_access_control
       WHERE username = p_username
       AND access_level = 'ADMINISTRATOR';
       RETURN l_count > 0;
     END;
     

   • Set the evaluation frequency (e.g., "Once per Session" for static roles or "Once per Page View" for dynamic roles).
   • Specify an error message (e.g., "Access Denied: Administrator privileges required.") for unauthorized access.

4. Applying Authorization Schemes to Components
   Apply the authorization schemes to restrict access to specific components:

   • Pages: In Page Designer, open the page, go to the Security tab, and select the authorization scheme (e.g., "Admin_Only") from the Authorization Scheme dropdown. This restricts the entire page to users with the specified role.
   • Regions: Select a region in Page Designer, navigate to the Security tab, and assign the scheme to control visibility or interactivity.
   • Buttons or Items: Apply the scheme to buttons (e.g., "Submit") or form items via their Security tab to restrict actions like editing or submitting.
   • Verify application by checking the Used In column in the Authorization Schemes list to see all components using the scheme.

5. Managing User-Role Assignments

   • Update user-role mappings dynamically via a form or PL/SQL process. Example: Create a form to manage the apex_access_control table, allowing administrators to assign roles.
   • After updating roles, reset the authorization scheme state to ensure immediate application of changes:

     BEGIN
       UPDATE apex_access_control
       SET access_level = 'EDITOR'
       WHERE username = :APP_USER;
       APEX_AUTHORIZATION.RESET_CACHE;
     END;
     

   • Ensure the form or process is secured with an authorization scheme to restrict access to authorized users (e.g., administrators).

6. Testing Access Control

   • Test the setup by logging in as users with different roles (e.g., Administrator, Editor, Viewer) to verify that access restrictions work as expected.
   • Use APEX Debug Mode or query the APEX_ACTIVITY_LOG view to troubleshoot issues with scheme evaluation or role assignments.
   • Confirm that error messages display clearly when access is denied.

7. Combining with Other Security Features

   • Combine access control with other APEX security features, such as Session State Protection (to prevent URL tampering) or Virtual Private Database (VPD) for row-level security.
   • Example: Use VPD to restrict data access based on roles stored in apex_access_control:

     BEGIN
       DBMS_RLS.ADD_POLICY (
         object_schema   => 'APP_SCHEMA',
         object_name     => 'EMPLOYEES',
         policy_name     => 'EMP_ACCESS',
         function_schema => 'APP_SCHEMA',
         policy_function => 'restrict_by_role'
       );
     END;
     FUNCTION restrict_by_role (p_schema IN VARCHAR2, p_object IN VARCHAR2) RETURN VARCHAR2 IS
     BEGIN
       RETURN 'EXISTS (SELECT 1 FROM apex_access_control WHERE username = SYS_CONTEXT(''USERENV'', ''SESSION_USER'') AND access_level = ''EDITOR'')';
     END;
     

Access control in Oracle APEX allows you to define and manage user permissions within an application. This is achieved through an Access Control List (ACL), which you can create using the Access Control Wizard. This wizard is accessible via the Create Application Wizard or the Create Page Wizard.

When you run the Access Control Wizard, it:

• Generates a management page for the access control list.

• Creates two tables in the application's default parsing schema to store access control data.

Understanding Access Levels and Roles

The access control list enables you to assign specific privileges to users within the application. These privileges determine what actions users can perform and correspond to predefined access roles:

• View Access (READER Role) – Users can view content but cannot make modifications.

• Edit Access (CONTRIBUTOR Role) – Users can make changes but do not have administrative control.

• Administration Access (ADMINISTRATOR Role) – Users have full control, including the ability to manage access control settings.

To enforce access restrictions on application pages and components, you must create an Authorization Scheme and associate it with the application.

Defining Additional Roles

Beyond the default roles, you can define custom roles through the Application Access Control page. Since roles are assigned to users, it is important to define roles before adding users.

Oracle APEX provides system views that allow you to review the access control settings:

• APEX_APPL_ACL_USERS – Displays user access details.

• APEX_APPL_ACL_USER_ROLES – Shows the roles assigned to users.

• APEX_APPL_ACL_ROLES – Lists all roles defined in the application.

Creating Custom Access Control Roles

To enhance security and customize access control, you can create new roles within the application. Before assigning users to roles, ensure that the necessary roles have been created. This structured approach ensures that each user has the appropriate level of access based on their role in the application.

Best Practices for Applying Access Control in Oracle APEX

• Follow Least Privilege: Assign users the minimum roles needed for their tasks to enhance security.
• Use Descriptive Role Names: Define clear role names (e.g., "ADMINISTRATOR," "EDITOR") to reflect their purpose and simplify maintenance.
• Centralize Role Management: Store user-role mappings in a single table (e.g., apex_access_control) for consistency across applications.
• Secure Role Updates: Restrict role assignment updates to authorized users (e.g., administrators) using authorization schemes.
• Optimize Evaluation Frequency: Use "Once per Session" for static roles to improve performance, or "Once per Page View" for dynamic role changes.
• Test Extensively: Validate access control in a development environment with various user scenarios to ensure correct behavior.
• Document Configurations: Maintain detailed records of roles, authorization schemes, and their application to components for easier troubleshooting.
• Monitor Access: Enable Application Activity Logging in Shared Components > Security Attributes to track access attempts and audit role assignments.

Oracle APEX Documentation
For comprehensive details on applying access control in Oracle APEX, refer to the official documentation:
Oracle APEX Application Access Control Documentation

Conclusion

Applying access control in Oracle APEX using the Application Access Control feature enables developers to implement robust, role-based security with ease. By defining roles, creating authorization schemes, and applying them to components, you can ensure that users access only the features and data they are authorized for. Following best practices and consulting the Oracle APEX documentation will help you maintain a secure and efficient application, adapting to evolving security requirements.