Pass the Salesforce Developers PDII Questions and answers with Dumpstech

18

In the Aura Component framework, communication between components is handled via events. When two components need to communicate but do19 not share a direct parent-child relationship—such as a kiosk registration component on a page and an alert component residing in the global utility tray—an Application Event (Option C) is required.

Application events follow a "publish-subscribe" model. One component fires the event, and any other component in the application that has a handler for that specific event type can listen for and react to it, regardless of where they sit in the component hierarchy. This is distinct from a Component Event (Option D), which is restricted to bubbling up the component containment hierarchy (from child to parent).

While modern implementations might also consider the Lightning Message Service (LMS) for cross-framework communication (between Aura, LWC, and Visualforce), within the specific context of Aura-to-Aura communication for decoupled components like utility bar items, Application Events remain the fundamental architectural solution. DML Operations (Option A) and ChangeLogs (Option B) are database-level concepts and do not provide the real-time, client-side notification capabilities needed for a UI alert system.

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For an Apex method to be reachable by a Lightning Web Component, it must be annotated with @AuraEnabled. In this code, line 03 is the entry point for the search functionality. Without the @AuraEnabled annotation on line 03 (Option D), the JavaScript controller will not be able to "see" or invoke the search method, resulting in a runtime error.

Furthermore, because this method returns a custom "Wrapper" class, the platform's serialization engine needs to know which specific properties within that wrapper class should be sent to the client-side JavaScript. By default, the LWC framework does not serialize class members unless they are explicitly marked. Therefore, the developer must add @AuraEnabled to lines 10 and 11 (Option C). Without this, even if the method executes successfully, the account and matchProbability properties will be stripped during the JSON conversion, and the component will receive a list of empty objects.

Adding @AuraEnabled to the class definitions themselves (Lines 01 or 09) is not required; the annotation is only necessary on the specific methods and member variables that participate in the data exchange between Apex and JavaScript. This explicit marking ensures security and efficiency by only exposing the data intended for the user interface.

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In Salesforce, all triggers that fire as a result of an initial DML operation ru39n within the same execution context and the same transaction. This means that all governor limits—such as the limit of 10,000 records processed by DML statements—are shared across the entire chain of events.

In this scenario, the transaction begins with the update of 200 Accounts. The Account trigger then attempts to update 10,000 related Contacts (50 Contacts per Account across 200 Accounts). This update of 10,000 Contacts then fires the Contact trigger, which attempts to update 10,000 related Campaign Members. When the system attempts to process these updates, the total number of records processed via DML in a single transaction will exceed the platform limit of 10,000 rows.

Even though the Account update is only 200 records, the subsequent cascading updates (10,000 Contacts + 10,000 Campaign Members) bring the total DML count to 20,200. This triggers a LimitException, and because Apex transactions are atomic, the entire operation will fail and roll back. To resolve this, the developer would need to handle these updates asynchronously (e.g., using Batch Apex or Queueable) to split the cascading updates into separate transactions with their own sets of governor limits.

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This requirement involves two specific databas26e events: record insertion (for setting defaults) and record deletion (for enforcing business rules/errors). Both Apex Triggers (Option A) and Flow Builder (Option C) are capable of handling these scenarios.

Flow Builder is the declarative (low-code) solution. A Record-Triggered Flow can be set to run "Before Save" to efficiently update the Contact's fields with metadata defaults upon insertion. Furthermore, Flow Builder now supports "Before Delete" triggers and the "Custom Error" element, allowing an administrator to block a deletion and present a specific error message to the user if the Contact belongs to a flagged region.

Apex Triggers are the programmatic solution. A developer can write a before insert trigger to perform the Custom Metadata lookup and assign field values, and a before delete trigger to evaluate the region and call addError() on the record.

Option B (Remote Action) is for Visualforce-to-Apex communication, and Option D (Invocable Method) is a piece of code called by a Flow or Process, not an entry point itself. Therefore, Triggers and Flows are the two primary automation frameworks for these requirements.

This query requires a specific understanding of how Salesforce handles old records. Salesforce "archives" Tasks that are older than 365 days to maintain performance. These archived records are not returned by standard SOQL queries.

To include archived records in a query, the developer must use the ALL ROWS keywords at the end of the query. However, ALL ROWS also returns records that are in the Recycle Bin (deleted records). To satisfy the requirement of "including archived" but "excluding deleted," the developer simply needs to rely on the fact that standard WHERE clause filters apply to the results of ALL ROWS.

Option B is the most accurate. In SOQL, isDeleted=false is implicit unless you are specifically looking for deleted records. The crucial part is the ALL ROWS keyword which brings the archived tasks into scope.

Options A and D are incorrect because isArchived=true would only return the archived tasks and exclude those that are not yet archived. Option C is redundant because isDeleted=false is the default behavior. The syntax => in the prompt options is also technically a typo for >=. Option B represents the standard way to query across the "active" and "archived" boundary while ignoring the Recycle Bin.

When building Apex controllers for Aura Components (or Lightning Web Components), any method annotated with @AuraEnabled must be defined as static. The snippet provided defines the method getStringArray() as an instance method (public List...) rather than a static method (public static List...).

The Lightning Component framework does not instantiate an object of the Apex class; instead, it calls the method statically. If the method is not static, the framework cannot locate or execute it, resulting in an error. While global was required in older versions or for managed packages, public is sufficient for code within the same namespace. Apex handles the serialization of standard types like Lists automatically, so manual JSON serialization is not required.

In Salesforce Apex triggers, choosing the correct context (before vs. after) is critical for performance and data integrity. When the business requirement involves creating or modifying related records (records other than the one that fired the trigger), an after trigger is the platform-standard choice.

An after update trigger (Option D) is ideal here because it ensures that the Case record has been successfully validated and saved to the database (obtaining a valid timestamp and state) before the child Engineering_Review__c record is generated. Furthermore, an after trigger provides access to the read-only Trigger.new and Trigger.old maps, which contain the final field values after system validation rules and flows have run. Performing DML operations to insert a new object within a before trigger is technically possible but discouraged, as it can lead to issues if the primary record fails a subsequent system validation, potentially leaving orphaned data or causing complicated rollback scenarios.

Options B and C are incorrect because "upsert" is not a valid trigger event; the valid events are insert, update, delete, and undelete. Option A is incorrect because before triggers should primarily be used for updating fields on the same record that initiated the trigger to avoid redundant DML calls. Therefore, an after update trigger provides the most stable and scalable context for cross-object record creation.

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In a multi-user environment, a "Race Condition" occurs when two users query the same record at the same time, see that Is_Registered__c is false, and both proceed to update it. To prevent this, developers must implement Row-Level Locking.

In Salesforce SOQL, the FOR UPDATE (Option C) keyword is used for this exact purpose. When a query includes FOR UPDATE, the platform places an exclusive lock on the records returned. If a second transaction attempts to query the same records using FOR UPDATE, it will be forced to wait until the first transaction is completed (either committed or rolled back). If the lock isn't released within 10 seconds, the second transaction throws a QueryException.

By using FOR UPDATE, the first user who executes the query "reserves" the Account. The second user's request will wait, and by the time their query actually executes and retrieves the data, Is_Registered__c will have been updated to true by the first user, thus failing the if (!account.Is_Registered__c) check and preventing a duplicate registration. Option D is a manual "optimistic locking" approach that is less reliable than the platform's native locking mechanism. Options A and B do not address the timing issue of the initial check.

In Visualforce, the standard behavior for an <apex:commandButton> is to perform a full page postback. To convert this into an asynchronous (AJAX) request that only updates a specific portion of the page, the developer must use the reRender attribute (D). By setting reRender="opportunityList" on the command button, the developer instructs the platform to capture the server's response and update only the DOM element with that specific ID, rather than refreshing the entire browser window.

While Option C (returning null from the search method) is a requirement for staying on the same page, it does not prevent the full refresh by itself. Option A (<apex:actionRegion>) is used to limit which part of the form's data is sent to the server for processing (to avoid validation errors on unrelated fields), but it does not control which part of the page is re-drawn on the client. Option B (<apex:actionFunction>) is a way to call Apex from JavaScript but doesn't solve the button's refresh behavior directly. Implementing reRender is the standard and most efficient way to achieve the "partial refresh" UX in Visualforce, significantly improving the perceived performance and user experience by reducing the amount of data and UI flickering during search operations.

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To optimize the performance of a Visualforce page that uses external assets, Static Resources (Option5 A) is the pl6atform-native best practice. Static resources allow you to upload content such as archives (.zip or .jar files), images, stylesheets, and JavaScript files that you can reference in a Visualforce page.

The primary benefits of using Static Resources over other methods (like hosting files externally or hardcoding styles) include:

Caching: Salesforce serves static resources from a Content Delivery Network (CDN). This means once a user's browser loads the JavaScript or CSS file, it is cached locally, significantly reducing page load times for subsequent requests.

Relative Referencing: Using the $Resource global variable (e.g., {!URLFOR($Resource.MyZipFile, 'styles/main.css')}) ensures that your page references the correct version of the file across different environments (Sandbox, Production) without changing hardcoded URLs.

Efficiency: By bundling related files into a single ZIP archive as a static resource, you reduce the number of HTTP requests the browser must make to render the page.

Options B and D are related to AJAX and JavaScript-to-Apex communication, and Option C is a component used for rendering data tables; none of these address the storage or caching of external front-end assets.