Salesforce PDI Exam Made Easy: Step-by-Step Preparation Guide

In a before insert trigger:

Trigger.old is null.

There is no existing record in the database to reference.

Why Not Other Options:

Option A: Describes Trigger.new.

Option B: The variable is defined but has a null value.

Option D: Trigger.old is not an empty list; it is null.

References:

Trigger Context Variables:

"In insert triggers, Trigger.old is null because the records are new."— Apex Developer Guide: Trigger Context Variables

To expose an Apex class as a RESTful web service, you use the @RestResource annotation.

Option C: @RestResource(urlMapping='/myService/*')

@RestResource Annotation:

The @RestResource annotation is used to define an Apex class as a RESTful web service, specifying the URL mapping.

Methods within the class are annotated with @HttpGet, @HttpPost, @HttpPut, etc., to handle HTTP requests.

Example:

apex

Copy code

@RestResource(urlMapping='/myService/*')

global with sharing class MyRestService {

@HttpGet

global static String doGet() {

// Implementation

}

}

In the Model-View-Controller (MVC) architecture applied to a Lightning Web Component (LWC) that imports an Apex method:

Controller refers to the logic that handles input and interactions.

In this scenario, when a button is pressed, the method runs to execute complex validations.

Option C: Apex class

Part of Controller.

Explanation:

The Apex class contains the method that performs the complex validations.

It acts as the server-side controller logic.

When overriding standard buttons in Salesforce Classic and Lightning Experience, different technologies are used.

Salesforce Classic:

Visualforce pages are used to override standard buttons like Edit.

Lightning Experience:

Lightning Components (Aura Components or Lightning Web Components) are used.

Option C: A Visualforce page in Salesforce Classic and a Lightning component in Lightning Experience

Correct Answer.

Explanation:

In Salesforce Classic, override the Edit button with a Visualforce page.

In Lightning Experience, use a Lightning Component to override the Edit action.

When deploying Apex code to a production environment, certain requirements must be met regarding test coverage and annotations.

Option B: Apex classes must have at least 75% code coverage org-wide.

Correct Requirement.

Explanation:

Salesforce requires that all Apex classes and triggers have a combined code coverage of at least 75% before deployment to production.

This means that, across all Apex code in the org, at least 75% of the code must be covered by test methods.

When building the database layer of a Salesforce application using exclusively declarative development, the following options are relevant:

Option A: Roll-up summaries

Valid Declarative Tool.

Explanation:

Roll-up summary fields allow calculations (SUM, COUNT, MIN, MAX) on child records in a master-detail relationship.

They are created declaratively.

To ensure that the variables creditAmount and debitAmount cannot change once assigned, the final keyword should be used.

Option B: Use the final keyword and assign its value in the class constructor.

Declaring a variable as final allows it to be assigned once.

Assigning the value in the constructor is acceptable for instance variables.

Option D: Use the final keyword and assign its value when declaring the variable.

Assigning the value at declaration ensures it cannot be changed later.

Why Not Other Options:

Option A: Using static with assignment in the constructor is invalid because static variables belong to the class, not instances.

Option C: Using static and assigning in a static initializer doesn't prevent reassignment unless final is also used.

References:

Final Variables:

"You can declare instance variables as final. A final variable can only be assigned a value once, either when you declare it or in the constructor."— Apex Developer Guide: Classes, Objects, and Interfaces

Universal Containers wants to prevent Opportunities from being edited once they reach the Closed/Won stage. To achieve this, the developer can use the following strategies:

Option A: Use a validation rule.

Correct Approach.

Explanation:

A validation rule can be created on the Opportunity object to prevent users from editing records when the Stage is Closed/Won.

The validation rule would evaluate whether the record's StageName is 'Closed Won' and, if so, display an error message when a user attempts to edit and save the record.

Example Validation Rule:

AND(

ISPICKVAL(StageName, 'Closed Won'),

ISCHANGED(ANYFIELD) // Replace ANYFIELD with specific fields if needed

)

Benefits:

Declarative Solution: No code required.

Consistent Enforcement: Applies across all user interfaces and API.

To add an additional layer of validation for email addresses on Lead records by using automation and possibly an external validation service, the best solution is to use a custom Lightning Web Component (LWC).

Option C: Use a custom Lightning Web Component to make a callout to validate the fields on a third-party system

Real-Time Validation: An LWC can perform client-side validation and make callouts to external systems to validate the email address as the user inputs data.

User Experience: Provides immediate feedback to the user, improving data quality at the point of entry.

Limitations: This solution works when data is entered through the UI using the LWC component.