rahulmalhotra

-> 'Create a Batch Class to opt out contact records from email, call and fax whose Unsubscribe Date has passed'

20,000 records -> total
200 records

How many batches?

-> 20,000 / 200 -> 100 batches in total

rahulmalhotra

/*
*	Author:- Rahul Malhotra
*	Description:- This batch class is used to update all contacts who have opted out of email, call and fax
*	Created:- 18-12-2021
*	Last Updated:- 18-12-2021
*/
public class UpdateContactsBatch implements Database.Batchable<sObject> {

    // * Return a maximum of 50 million records
    public Database.QueryLocator start(Database.BatchableContext batchableContext) {

rahulmalhotra

let inputs = document.getElementsByTagName('input');
for(let input of inputs) {
    if(input.type === 'checkbox' && input.name === 'enable') {
        input.disabled = false;
        break;
    }
}

rahulmalhotra

-----------------------------------------------------------------------------------------
-> Sort a list of sObject records based on field value
-----------------------------------------------------------------------------------------

List<Account> accounts = new List<Account>();
accounts.add(new Account(
    Name = 'Hooli',
    NumberOfEmployees = 50,
    AnnualRevenue = 10000
));

rahulmalhotra

-------------
Enums in Apex
--------------

An enum is an abstract data type whose values consist of a finite set of identifiers.
Enums are typically used to define a set of possible values that don’t otherwise have a numerical order.

public enum Color { RED, BLUE, GREEN, ORANGE, PURPLE }

values()

rahulmalhotra

---------------------------------------------------------------------------------------------------------------------------
Custom Comparator
---------------------------------------------------------------------------------------------------------------------------

List<Integer> numbers = new List<Integer>{ 5, 3, 2, 1, 4 };
System.debug('Initial list of Integers => ' + numbers);

System.debug('Sorting Integers....');
numbers.sort();

rahulmalhotra

// * Link accounts with parent accounts

Update 10,000 accounts
-----------------------

// * Brute Force Approach - Very time consuming

List<Account> accounts = [SELECT Reference_ID__c, Parent_Reference_ID__c FROM Account];
List<Account> accountsToUpdate = new List<Account>();

rahulmalhotra

Map advanced methods:
----------------------

keySet(): Get all keys from a map
-------------------------------------

Map<Integer, String> employeesMap = new Map<Integer, String>{
    1 => 'Richard',
    2 => 'Monica',
    3 => 'Erlich',

rahulmalhotra

Map Data Structure in Apex
-------------------------------

Def: A map is a collection of key-value pairs where each unique key maps to a single value.

1. Creating a Map of Employees
-------------------------------

Map<Integer, String> employeesMap = new Map<Integer, String>();
System.debug(employeesMap);

rahulmalhotra

Convert Set to List
---------------------

Set<Integer> numbers = new Set<Integer>{30,30,30,20,20,10,40,40};
System.debug('Initial Set -> ' + numbers);

List<Integer> numbersList = new List<Integer>(numbers);
System.debug('List from Set -> ' + numbersList);

System.debug('Number at index 2 = ' + numbersList[2]);