In Oracle APEX, If Condition Directives are powerful tools that enable developers to control the rendering of templates and page components based on dynamic conditions. By using these directives, you can create flexible user interfaces that adapt to different user roles, session states, or application logic without the need for complex coding. Understanding how to create and use If Condition Directives allows you to build more personalized and responsive applications efficiently.
To create an If Condition Directive, navigate to Shared Components > Templates > Condition Directives. Here, you define a unique directive name and specify the PL/SQL Boolean expression that evaluates the condition. For example, you might create a directive named "IS_ADMIN" with a condition that checks if the current user has an admin role. This directive can then be referenced inside your templates using the syntax #IF IS_ADMIN# ... #END_IF#. When the condition evaluates to true, the enclosed content is rendered; otherwise, it is omitted.
Using If Condition Directives inside page templates or HTML regions allows fine-grained control over UI elements. You can create multiple directives for different user roles or application states, combining them to show or hide buttons, menu entries, or entire page sections. This method enhances maintainability by centralizing conditional logic and avoiding scattered PL/SQL or JavaScript checks.
When implementing these directives, ensure your PL/SQL conditions are efficient and consider caching their results if used repeatedly. Testing each directive thoroughly in different user contexts is also essential to guarantee the correct UI experience.
Overall, APEX If Condition Directives are a powerful feature to deliver dynamic and role-based content, helping you design cleaner, more responsive applications with minimal code overhead.
Example
In Oracle APEX, If condition directives are used to dynamically control the behavior and content of your pages based on certain conditions. They allow you to use conditional logic (similar to IF statements in programming) directly in your APEX application. These directives enable you to show or hide regions, items, or perform specific actions based on values like the current user, session, or specific conditions within your data.
The If condition directives are often used in regions, dynamic actions, and SQL queries. In this tutorial, we will cover the basics of these directives and provide practical examples of how to use them in Oracle APEX.
Step 1: Understanding If Condition Directives
APEX If condition directives allow you to check conditions dynamically and display or execute content based on the evaluation of those conditions.
Syntax of the IF Directive
The syntax of the IF directive in APEX is:
#{if <condition>}
<content>
#{else}
<alternative_content>
#{/if}
: This is the condition you want to evaluate. It can be a comparison between values, checking session variables, or even page item values.
: The content that will be displayed or action executed if the condition is true.
<alternative_content>: The content to be displayed or action to be executed if the condition is false (optional).
#{/if}: This ends the if block.
Step 2: Using IF Condition Directives in APEX
Let’s explore a few practical examples of how to use If condition directives in various scenarios in Oracle APEX.
Example 1: Showing Content Based on Session Variables
You can use the IF directive to show different content based on the session variables or page items, such as displaying a personalized message for the logged-in user.
Steps:
Create a Static Content Region on your page.
In the HTML Expression field, add the following code:
#{if &APP_USER. == 'ADMIN'}
<h2>Welcome, Administrator!</h2>
<p>You have full access to the application.</p>
#{else}
<h2>Welcome, &APP_USER.!</h2>
<p>Limited access based on your role.</p>
#{/if}
Explanation: In this example, if the logged-in user (&APP_USER.) is "ADMIN", the region will display a message for the administrator. Otherwise, it will display a generic message for all other users.
Expected Output:
If the logged-in user is "ADMIN":
Welcome, Administrator!
You have full access to the application.
If the logged-in user is not "ADMIN":
Welcome, JohnDoe!
Limited access based on your role.
Example 2: Show or Hide Regions Based on Item Value
You can also use If condition directives to conditionally show or hide regions based on a page item value.
Steps:
Create a Page Item: Create a page item (e.g., a checkbox or select list) called P1_SHOW_DETAILS.
Create a Region: Create a Static Content region where you want to display conditional content.
In the HTML Expression field, use the following code:
#{if :P1_SHOW_DETAILS == 'Y'}
<h3>Details Section</h3>
<p>This section contains additional information.</p>
#{else}
<h3>Details Section</h3>
<p>This section is hidden because the checkbox is not checked.</p>
#{/if}
Explanation: This code checks the value of P1_SHOW_DETAILS (a page item). If it is set to 'Y' (checked or selected), the content in the if block is shown. Otherwise, the else block content is shown.
Expected Output:
If P1_SHOW_DETAILS is set to 'Y':
Details Section
This section contains additional information.
If P1_SHOW_DETAILS is set to 'N':
Details Section
This section is hidden because the checkbox is not checked.
Example 3: Conditional Display of Regions Based on Application Item
You can conditionally display regions based on application items, such as checking whether a user is logged in or not.
Steps:
Create an Application Item: Create an application item, e.g., APP_USER_LOGGED_IN.
Set the Application Item: You can set APP_USER_LOGGED_IN in a login process to 'Y' if the user is logged in.
Create a Region: Add a Static Content region with the following HTML Expression:
#{if :APP_USER_LOGGED_IN == 'Y'}
<h2>Welcome back, &APP_USER.!</h2>
<p>Your previous session was restored.</p>
#{else}
<h2>Welcome to the Application</h2>
<p>Please log in to access your data.</p>
#{/if}
Explanation: This will display a message to the user based on whether they are logged in or not. The APP_USER_LOGGED_IN application item determines if the user is logged in.
Expected Output:
If APP_USER_LOGGED_IN is 'Y':
Welcome back, JohnDoe!
Your previous session was restored.
If APP_USER_LOGGED_IN is 'N':
Welcome to the Application
Please log in to access your data.
Example 4: Using IF Directive in Dynamic Actions
You can also use the IF condition within Dynamic Actions to execute actions based on conditions, such as page item values or session states.
Steps:
Create a Page Item: Create a page item (e.g., P1_STATUS).
Create a Dynamic Action: Create a Dynamic Action triggered by a change in P1_STATUS.
Set the Action Type: Use Execute JavaScript as the action and add the following JavaScript code:
if ("#{P1_STATUS}" == "ACTIVE") {
alert("The status is active!");
} else {
alert("The status is not active.");
}
Explanation: This JavaScript code checks the value of the P1_STATUS page item. If it is set to 'ACTIVE', it shows an alert stating that the status is active. Otherwise, it shows a different message.
Expected Output:
If P1_STATUS is "ACTIVE":
Alert: "The status is active!"
If P1_STATUS is not "ACTIVE":
Alert: "The status is not active."
Step 3: Advanced Conditional Logic
You can combine multiple conditions using AND, OR, and other logical operators to create more advanced logic within your IF directives.
Example: Check Multiple Conditions
#{if &APP_USER. == 'ADMIN' && :P1_STATUS == 'ACTIVE'}
<p>Welcome back, Admin. The status is active!</p>
#{else}
<p>Either you are not an Admin, or the status is not active.</p>
#{/if}
Explanation: In this case, the IF condition checks two things: if the user is "ADMIN" and if the page item P1_STATUS is set to 'ACTIVE'. If both conditions are true, the first message will be displayed. Otherwise, the else message will be shown.
By using these directives, you can create flexible and responsive applications that adapt to different user interactions, session states, or data values.
Mastering the use of APEX If Condition Directives empowers you to deliver tailored experiences within your applications by conditionally displaying or hiding content based on runtime conditions. This capability enhances the user interface’s relevance and usability while simplifying development through declarative controls. By integrating If Condition Directives thoughtfully, you can significantly improve the flexibility and maintainability of your Oracle APEX applications.
