trigger ContactCountTrigger on Contact (after insert, after update, after delete, after undelete) { Set<Id> accIds = new Set<Id>(); for (Contact c : (Trigger.isDelete ? Trigger.old : Trigger.new)) { if (c.AccountId != null) accIds.add(c.AccountId); } List<AggregateResult> results = [SELECT AccountId, COUNT(Id) cnt FROM Contact WHERE AccountId IN :accIds GROUP BY AccountId]; Map<Id, Integer> countMap = new Map<Id, Integer>(); for (AggregateResult ar : results) { countMap.put((Id) ar.get('AccountId'), (Integer) ar.get('cnt')); } List<Account> accsToUpdate = new List<Account>(); for (Id accId : accIds) { accsToUpdate.add(new Account(Id = accId, Total_Contacts__c = countMap.containsKey(accId) ? countMap.get(accId) : 0)); } if (!accsToUpdate.isEmpty()) update accsToUpdate; }

Account acc = [SELECT Id, (SELECT Id FROM Contacts) FROM Account WHERE Id = :accId]; Integer contactCount = acc.Contacts.size();

List<Id> jobIds = new List<Id>{ jobId1, jobId2, jobId3, jobId4 }; Integer totalProcessed = 0; Integer totalFailed = 0; for (AsyncApexJob job : [SELECT JobItemsProcessed, NumberOfErrors FROM AsyncApexJob WHERE Id IN :jobIds]) { totalProcessed += job.JobItemsProcessed; totalFailed += job.NumberOfErrors; }

// After insert — unset old "recent" flags for the same Account, keep only the newest trigger SubscriberTrigger on Subscriber__c (after insert, after delete) { if (Trigger.isInsert) { Set<Id> accIds = new Set<Id>(); for (Subscriber__c s : Trigger.new) accIds.add(s.Account__c); List<Subscriber__c> toUnset = [SELECT Id FROM Subscriber__c WHERE Account__c IN :accIds AND Recent_Subscriber__c = true AND Id NOT IN :Trigger.newMap.keySet()]; for (Subscriber__c s : toUnset) s.Recent_Subscriber__c = false; update toUnset; } if (Trigger.isDelete) { Set<Id> accIds = new Set<Id>(); for (Subscriber__c s : Trigger.old) accIds.add(s.Account__c); // Re-flag latest remaining Subscriber per Account (grouped in Apex after query, ordered by CreatedDate DESC) } }

trigger PreventAccountDelete on Account (before delete) { Set<Id> accIds = Trigger.oldMap.keySet(); Set<Id> accIdsWithOpps = new Set<Id>(); for (Opportunity o : [SELECT AccountId FROM Opportunity WHERE AccountId IN :accIds]) { accIdsWithOpps.add(o.AccountId); } for (Account acc : Trigger.old) { if (accIdsWithOpps.contains(acc.Id)) { acc.addError('Cannot delete an Account that has related Opportunities.'); } } }

// Aggregate query grouped by Account and Product, ordered by total quantity descending, // then keep only the top row per Account before updating the picklist field. List<AggregateResult> results = [SELECT Order.AccountId acc, Product2.Name prodName, SUM(Quantity) totalQty FROM OrderItem WHERE Order.AccountId IN :accIds GROUP BY Order.AccountId, Product2.Name ORDER BY Order.AccountId, SUM(Quantity) DESC];

Set<Id> accIds = new Set<Id>(); for (Contact c : Trigger.isDelete ? Trigger.old : Trigger.new) accIds.add(c.AccountId); Map<Id, Integer> accIdToCount = new Map<Id, Integer>(); for (AggregateResult ar : [SELECT AccountId, COUNT(Id) cnt FROM Contact WHERE AccountId IN :accIds GROUP BY AccountId]) { accIdToCount.put((Id) ar.get('AccountId'), (Integer) ar.get('cnt')); } List<Account> toUpdate = new List<Account>(); for (Id accId : accIds) { toUpdate.add(new Account(Id = accId, Total_Contacts_Count__c = accIdToCount.containsKey(accId) ? accIdToCount.get(accId) : 0)); } update toUpdate;

trigger AccountOwnerSync on Account (after update) { Set<Id> changedAccIds = new Set<Id>(); for (Account acc : Trigger.new) { if (acc.OwnerId != Trigger.oldMap.get(acc.Id).OwnerId) { changedAccIds.add(acc.Id); } } if (changedAccIds.isEmpty()) return; Map<Id, Id> accIdToNewOwner = new Map<Id, Id>(); for (Account acc : Trigger.new) { if (changedAccIds.contains(acc.Id)) accIdToNewOwner.put(acc.Id, acc.OwnerId); } List<Contact> contactsToUpdate = new List<Contact>(); for (Contact c : [SELECT Id, AccountId FROM Contact WHERE AccountId IN :changedAccIds]) { c.OwnerId = accIdToNewOwner.get(c.AccountId); contactsToUpdate.add(c); } update contactsToUpdate; }

trigger OppTestSync on Opportunity (after insert, after delete) { Set<Id> accIds = new Set<Id>(); for (Opportunity o : Trigger.isDelete ? Trigger.old : Trigger.new) accIds.add(o.AccountId); Map<Id, List<String>> accToValues = new Map<Id, List<String>>(); for (Opportunity o : [SELECT AccountId, Test__c FROM Opportunity WHERE AccountId IN :accIds]) { if (!accToValues.containsKey(o.AccountId)) accToValues.put(o.AccountId, new List<String>()); if (o.Test__c != null) accToValues.get(o.AccountId).add(o.Test__c); } List<Account> toUpdate = new List<Account>(); for (Id accId : accIds) { String combined = accToValues.containsKey(accId) ? String.join(accToValues.get(accId), ', ') : ''; toUpdate.add(new Account(Id = accId, Test__c = combined)); } update toUpdate; }

// Example snippet type asked: trigger OppMapTrig on Opportunity (before insert) { Map<Id, Account> accMap = new Map<Id, Account>(); for (Opportunity o : Trigger.new) { o.Description = accMap.get(o.AccountId).Industry; // NullPointerException — map is never populated } }

handleRefreshClick() { refreshApex(this.wiredAccounts); }

export default class MyComponent extends LightningElement { constructor() { super(); this.internalCounter = 0; } }

import { publish, subscribe, MessageContext } from 'lightning/messageService'; import MY_CHANNEL from '@salesforce/messageChannel/MyChannel__c';

@wire(getContactsForAccount, { accountId: '$recordId' }) contacts;

@AuraEnabled(cacheable=true) public static List<Account> getAccounts() { return [SELECT Id, Name FROM Account]; }

connectedCallback() { /* subscribe to LMS */ } disconnectedCallback() { /* unsubscribe from LMS */ }

const inputs = this.template.querySelectorAll('lightning-input'); inputs.forEach(input => { input.reportValidity(); });

handleSelectAll() { this.records = this.records.map(rec => ({ ...rec, isSelected: true })); } handleDeselectAll() { this.records = this.records.map(rec => ({ ...rec, isSelected: false })); }

-- Diagnostic order: -- 1. Object/Field permissions (Profile + Permission Sets) -- 2. OWD for the object -- 3. Role hierarchy (if grant-access-using-hierarchy is on) -- 4. Sharing rules (criteria or ownership-based) -- 5. Manual sharing / Apex-managed sharing

-- Checklist when Share button is missing: -- OWD already Public R/W? -> button hidden by design -- Object supports sharing at all? -- Profile permission for sharing action present?

-- Record detail page -> Sharing -> Add -> select User/Role/Group -> Access Level

public without sharing class DataMigrationHelper { // Explicitly documented: intentionally bypasses sharing for admin migration tasks }

-- Layers, broad to narrow: -- Org-level -> Object-level -> Field-level -> Record-level

-- Setup -> Sharing Sets -> New -- Access Mapping: Case.Contact = User's Contact (Related to logged-in user)

-- Review: Guest User Profile -> Object permissions -- Review: Sharing Set field mappings -- Review: OWD for externally-exposed objects

// Trigger bypass check if (!BypassSettings__c.getInstance().Bypass_Triggers__c) { // run trigger logic }

global class CleanupBatch implements Database.Batchable<sObject> { global Database.QueryLocator start(Database.BatchableContext bc) { return Database.getQueryLocator([SELECT Id FROM Lead WHERE IsConverted = false AND CreatedDate < LAST_N_DAYS:365]); } global void execute(Database.BatchableContext bc, List<sObject> scope) { } global void finish(Database.BatchableContext bc) { } }

global Database.QueryLocator start(Database.BatchableContext bc) { if (Batch_Control__mdt.getInstance('ExpireRecordsBatch').Skip_Next_Run__c) { return Database.getQueryLocator([SELECT Id FROM MyObject__c WHERE Id = null]); // empty scope } return Database.getQueryLocator([SELECT Id, Expire_Date__c FROM MyObject__c WHERE Status__c = 'Active']); }

AND( CloseDate < TODAY(), NOT($Permission.Bypass_Close_Date_Validation) )

// Anti-pattern that burns CPU time, not DB time: for (Account a : accountList) { for (Contact c : contactList) { // O(n^2) nested loop -- pure CPU cost if (c.AccountId == a.Id) { /* ... */ } } }

global class ExpireRecordsBatch implements Database.Batchable<sObject>, Schedulable { global Database.QueryLocator start(Database.BatchableContext bc) { return Database.getQueryLocator([SELECT Id, Status__c FROM My_Object__c WHERE Status__c = 'Active' AND Expire_Date__c < TODAY()]); } global void execute(Database.BatchableContext bc, List<My_Object__c> scope) { for (My_Object__c rec : scope) rec.Status__c = 'Inactive'; update scope; } global void finish(Database.BatchableContext bc) {} global void execute(SchedulableContext sc) { Database.executeBatch(new ExpireRecordsBatch()); } }

Map<Id, Account> accMap = new Map<Id, Account>([SELECT Id, Industry FROM Account WHERE Id IN :accIds]); for (Opportunity o : opps) { o.Description = accMap.get(o.AccountId).Industry; // O(1) lookup }

public class MyQueueable implements Queueable { public void execute(QueueableContext context) { // can enqueue another Queueable here -- chaining System.enqueueJob(new NextStepQueueable()); } }

@future public static void sendWelcomeEmails(List<Id> contactIds) { List<Contact> freshContacts = [SELECT Id, Email FROM Contact WHERE Id IN :contactIds]; // send emails using current data, not a stale snapshot }

-- OAuth 2.0 grant types commonly discussed: -- Web Server Flow, User-Agent Flow, JWT Bearer Flow, Device Flow, Client Credentials Flow

HttpRequest req = new HttpRequest(); req.setEndpoint('callout:My_Named_Credential/api/orders'); req.setMethod('GET');

-- Access token: short-lived, used on every API call -- Refresh token: long-lived, exchanged for a fresh access token when needed

Order_Status_Change__e event = new Order_Status_Change__e(Status__c = 'Shipped', Order_Id__c = orderId); EventBus.publish(event);

List<Contact> contacts = [SELECT Id, Email, FirstName, LastName FROM Contact WITH USER_MODE]; // deliberately excludes sensitive custom fields not needed by the external system

-- IsPersonAccount field distinguishes Person Accounts from Business Accounts on the same object

SELECT Id, Name FROM Account WHERE IsPersonAccount = true AND CreatedDate = LAST_N_DAYS:4

-- ARC config: Setup -> Actionable Relationship Center Settings -- Action Plan: built from an Action Plan Template, applied to a record

SELECT Id, Subject, TextBody, FromAddress, MessageDate FROM EmailMessage WHERE ParentId = :caseId ORDER BY MessageDate ASC

-- Simple field default -> Record-Triggered Flow (before-save) -- Complex multi-object rollups, recursion control -> Apex Trigger + Handler class

renderedCallback() { if (this.chartInitialized) return; this.chartInitialized = true; const canvas = this.template.querySelector('canvas'); // initialize third-party library against the real DOM node }

// Reassigning triggers reactivity automatically -- no @track needed for this this.records = [...this.records, newRecord];

<template lwc:if={isApproved}> <lightning-badge label="Approved"></lightning-badge> </template> <template lwc:elseif={isPending}> <lightning-spinner></lightning-spinner> </template> <template lwc:else> <lightning-badge label="Rejected" variant="error"></lightning-badge> </template>

// In the parent, listening to sibling A's event and updating sibling B's input handleFilterChange(event) { this.selectedFilter = event.detail.value; // passed to sibling B via @api }

async handleSave(event) { const updatedFields = event.detail.draftValues; await updateOpportunities({ opps: updatedFields }); this.draftValues = []; await refreshApex(this.wiredOpps); }

@AuraEnabled(cacheable=true) public static List<Case> getCasesPage(Id lastId, Integer pageSize) { String query = 'SELECT Id, Subject FROM Case '; if (lastId != null) query += 'WHERE Id > :lastId '; query += 'ORDER BY Id LIMIT :pageSize'; return Database.query(query); }

-- Techniques: pagination/virtualization, lazy-loading, avoiding nested for:each, -- batching reactive updates, cacheable wire methods to avoid redundant server calls

handleSearchInput(event) { window.clearTimeout(this.delayTimeout); const searchTerm = event.target.value; this.delayTimeout = setTimeout(() => { this.performSearch(searchTerm); }, 300); }

try { await saveOpportunity({ opp: this.record }); } catch (error) { const message = error.body?.message || 'An unexpected error occurred'; this.dispatchEvent(new ShowToastEvent({ title: 'Error', message, variant: 'error' })); }

-- Tools: Chrome DevTools Performance tab, Lightning Component Inspector, -- Network tab (look for duplicate/redundant Apex calls), console.time()/console.timeEnd()

import { createElement } from 'lwc'; import MyComponent from 'c/myComponent'; import getAccounts from '@salesforce/apex/AccountController.getAccounts'; jest.mock('@salesforce/apex/AccountController.getAccounts', () => ({ default: jest.fn() }), { virtual: true });

-- Never rely on hiding a field in the template as "security" -- Query only what's needed, enforce FLS server-side with WITH USER_MODE

@AuraEnabled(cacheable=true) public static List<Contact> getContacts(Id accountId) { return [SELECT Id, Name, Email FROM Contact WHERE AccountId = :accountId WITH USER_MODE]; }

-- One Opportunity object, three Record Types (BrandA, BrandB, BrandC) -- Approval Process entry criteria: RecordType.DeveloperName = 'BrandB_Opportunity'

-- 1. Test in sandbox with production data volume -- 2. Bypass automation via Custom Setting -- 3. Bulk API update during off-hours -- 4. Validate sample records, re-enable automation -- 5. Notify affected sales reps of the cutover

Shipment__c ship = new Shipment__c(Idempotency_Key__c = new Uuid().toString()); insert ship; // same key reused on every retry attempt for this shipment

-- Setup -> Business Hours -> configure holidays -- Setup -> Entitlement Process -> Milestone using that Business Hours record

-- Identify duplicates via Matching Rule -- For matches: Lead Convert against existing Account/Contact (not delete) -- Re-parent CampaignMember to preserve attribution

-- Batch Apex reparents Contacts in scope-sized chunks (normal DML, rollups fire naturally) -- Post-migration: validate rollup totals via aggregate query on a sample of old + new parents

-- Custom Metadata Type: Approval_Routing__mdt -- Fields: Region__c, Min_Amount__c, Max_Amount__c, Approver__c -- Flow queries this table to dynamically set the Submit for Approval assignee

-- Native rollup: sums raw Amount, ignoring currency -- broken for multi-currency orgs -- Fix: roll up Amount (converted) field, or use an Apex/Flow-based rollup -- that explicitly converts each child to the Account's currency

-- Checklist: -- 1. External OWD for Opportunity -- should be Private -- 2. Sharing Set / Sharing Rule scope -- must be Account-relationship-based, not Role-based -- 3. Partner Super User checkbox -- verify it's not over-granted

-- 1. Reschedule batch to run fully before regional business hours -- 2. Reduce batch scope size for faster per-chunk commit -- 3. Add retry-with-backoff for the rare remaining lock conflict

Opportunity newOpp = originalOpp.clone(false, true, false, false); insert newOpp; List<OpportunityContactRole> newRoles = new List<OpportunityContactRole>(); for (OpportunityContactRole ocr : [SELECT ContactId, Role, IsPrimary FROM OpportunityContactRole WHERE OpportunityId = :originalOpp.Id]) { newRoles.add(new OpportunityContactRole(OpportunityId = newOpp.Id, ContactId = ocr.ContactId, Role = ocr.Role, IsPrimary = ocr.IsPrimary)); } insert newRoles;

@future public static void stepOne() { // stepTwo(); -- NOT ALLOWED if stepTwo is also @future, throws an exception }

-- Custom Metadata: deploys with the package, ideal for per-environment config that moves with releases -- Custom Setting: data only, must be populated separately per org after deployment