Complete PDI Salesforce Materials

Comprehensive and Detailed Explanation From Exact Extract:

A (Correct):AnApproval Processcan lock a record (making it read-only) once the record meets certain criteria like stage = Closed/Won.

B (Correct):AValidation Rulecan prevent users from saving changes when the stage is Closed/Won, by throwing an error.

Example validation formula:

text

CopyEdit

AND(ISCHANGED(StageName), ISPICKVAL(StageName, "Closed Won"))

Incorrect options:

C:Before triggers run before the record is saved but don’t prevent UI-level edits unless combined with DML rollbacks or errors.

D:Auto-response rules are for sending emails, not restricting edits.

The@AuraEnabled(cacheable=true)annotation makes an Apex method available to Lightning Web Components and allows it to be wired to a property while enabling client-side caching for improved performance.

Below is the formatted response for the provided question, adhering to the specified format and requirements. The question falls under the Developer Fundamentals topic, as it involves understanding Apex class inheritance and virtual classes, which are core concepts in the Salesforce Platform Developer I certification. The answer is based on official Salesforce Platform Developer I documentation, with a comprehensive explanation and references to relevant Salesforce documentation.

Trigger.old in a before insert trigger:

TheTrigger.oldcontext variable contains the old version of the records being processed in the trigger.

In abefore inserttrigger, the records being processed are new and have no prior state in the database, soTrigger.oldisnull.

This behavior is specific to insert triggers because there is no "old" record to reference before the record is created.

Why is it null?

The Trigger.old variable is only populated for triggers that handle updates or deletions (e.g., before update, after update, before delete, after delete). For insert operations, no previous state of the record exists.

Why not the other options?

A. An empty list of sObjects:

This is incorrect because Trigger.old is not initialized as an empty list for insert triggers—it is simply null.

B. Undefined:

Trigger.old is defined in the trigger context, but it is null for insert operations. Undefined is not a valid Apex state.

D. A list of newly created sObjects without IDs:

This describes Trigger.new in abefore inserttrigger, not Trigger.old. Trigger.new contains the new records being inserted.