Apex Data Types and Variables: Learn Salesforce Apex with Example

Introduction

Welcome to Lesson 2 in our Salesforce Apex series! In this lesson, we will cover Apex data types and variables—the basic building blocks of Apex programming.

A variable is a placeholder used to store and manipulate data. Every variable in Apex has a data type, which defines what kind of values it can hold.

By the end of this guide, you’ll be able to: ✅ Understand different Apex data types
✅ Declare and use variables
✅ Manipulate strings and dates
✅ Complete a hands-on coding assignment

1️⃣ Data Types in Apex

Apex supports different kinds of data types, which are categorized as primitive types and complex types.

🔹 Primitive Data Types (Basic types)

These are the simplest types of data in Apex.

Data Type	Description	Example
`Integer`	Whole numbers	`Integer num = 10;`
`Double`	Decimal numbers	`Double price = 99.99;`
`Boolean`	True/False values	`Boolean isActive = true;`
`String`	Text values	`String name = 'Rakesh';`
`Date`	Stores only a date	`Date today =` `Date.today();`
`Time`	Stores only time	`Time now =` `Time.now();`
`Datetime`	Stores both date & time	`Datetime current =` `Datetime.now();`
`Long`	Large whole numbers	`Long bigNum = 123456789L;`
`ID`	Salesforce record ID	`Id userId = UserInfo.getUserId();`

🔹 Complex Data Types

These allow for storing multiple values.

Data Type	Description	Example
`List<T>`	Ordered collection	`List<String> names = new List<String>();`
`Set<T>`	Unique values only	`Set<Integer> uniqueNums = new Set<Integer>();`
`Map<K, V>`	Key-value pairs	`Map<String, Integer> scoreMap = new Map<String, Integer>();`
`SObject`	Salesforce Object	`Account acc = new Account();`

2️⃣ Declaring Variables

To create a variable in Apex, use this format:

dataType variableName = value;

Example:

Integer age = 25;
String fullName = 'Rakesh Neelam';
Boolean isAdmin = false;

3️⃣ Constants (Final Variables)

A constant is a variable that cannot be changed after being set.

final Integer MAX_USERS = 100;

❌ Trying to reassign MAX_USERS = 200; will cause an error.

4️⃣ Working with Strings

Apex provides several string methods to manipulate text.

String greeting = 'Hello, Salesforce!';
System.debug(greeting.toUpperCase()); // "HELLO, SALESFORCE!"
System.debug(greeting.length()); // 18
System.debug(greeting.substring(0, 5)); // "Hello"

5️⃣ Working with Dates and Datetime

Apex has built-in methods for date and time manipulation.

Date today = Date.today();
System.debug(today); // Prints today's date

Datetime currentTime = Datetime.now();
System.debug(currentTime); // Prints current date and time

🔹 Assignment 2: Practice with Variables

Your Task:

Create an Apex class named DataTypeExample.
Inside the class, declare:
- An Integer variable with your age.
- A String variable with your full name.
- A Boolean variable to check if today is a weekend.
- A Date variable with today’s date.
- A Datetime variable with the current timestamp.
Print all variables using System.debug().
Execute the class using Anonymous Apex.

Example Solution (Try Writing it Yourself First!):

public class DataTypeExample {
    public static void showVariables() {
        Integer age = 28;
        String fullName = 'John Doe';
        Boolean isWeekend = (Date.today().dayOfWeek() == 6 || Date.today().dayOfWeek() == 7);
        Date today = Date.today();
        Datetime currentTime = Datetime.now();

        System.debug('Age: ' + age);
        System.debug('Full Name: ' + fullName);
        System.debug('Is it Weekend?: ' + isWeekend);
        System.debug('Today's Date: ' + today);
        System.debug('Current Time: ' + currentTime);
    }
}

To execute:

DataTypeExample.showVariables();

Apex Data Types and Variables: A Beginner's Guide