Gain insights into object-oriented programming in PHP. Discover classes, objects, methods, inheritance, and more. Build dynamic server-side applications using OOP techniques and PHP database management.

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Object-oriented programming is perhaps the dominant development paradigm for leading languages including Java, C#, and Python. The rich class and inheritance framework wasn’t fully implemented in modern PHP until 2015, and best practices for object-oriented programming are still emerging.

This course is an introduction to object-oriented programming in PHP. You’ll start with the basics of the OOP paradigm and get familiar with classes, objects, methods, and properties. You’ll then chain methods and properties using the this keyword before working with access modifiers and magic methods. With these basics down, you’ll take a deep dive into object-oriented programming in PHP, including inheritance, abstraction, polymorphism, and namespaces. After exploring exception handling, you’ll use these object-oriented techniques to build, manage, and edit a PHP database.

By the end of this course, you’ll be prepared to build dynamic server-side applications using object-oriented programming in PHP.

Object-Oriented Programming in PHP

# The `public` access modifier

The `public` **access modifier** allows code from both outside and inside the class to access the class’s methods and properties.

## How to access a public property

In the following example, the class’s property and method are defined as `public`, so the code outside the class can directly interact with them.

<?php
class Car {
  // Public methods and properties
  public $model;

  public function getModel() 
  {
    return "The car model is " . $this -> model; 
  }
}

$mercedes = new Car();

// Here we access a property from outside the class
$mercedes -> model = "Mercedes";

// Here again we access another method from outside the class
echo $mercedes -> getModel();
?>

In **line 15**, we set the `public` property `$model` outside the class. In **line 18**, we call the `public` method `getModel()` from outside the class.  

# The `private` access modifier

The `private` **access modifier** prevents access to a class’s methods or properties from any code outside the class. We can prevent access to the properties and methods inside our classes if we define them with the` private` access modifier instead of the `public` access modifier.

In the following example, we define the property `$model` as `private`. When we try to set its value from outside the class, we encounter a fatal error.


In **line 15**, we set the `public` property `＄model` outside the class. In **line 18**, we call the `public` method `getModel()` from outside the class.  

# The `private` access modifier

The `private` **access modifier** prevents access to a class’s methods or properties from any code outside the class. We can prevent access to the properties and methods inside our classes if we define them with the` private` access modifier instead of the `public` access modifier.

In the following example, we define the property `＄model` as `private`. When we try to set its value from outside the class, we encounter a fatal error.


Learn about the public and private access modifiers and how they can be accessed from outside the class.

Introduction

Classes and Objects

Using the $this Keyword for Chaining Methods and Properties

Access Modifiers

Magic Methods and Constants Unveiled

Inheritance in Object-oriented Programming

Abstract Classes and Interfaces

Polymorphism and Type Hinting

Static Methods & Properties and Traits

Namespaces & Dependency Injection

Exception Handling

PHP Database

Model-view-controller (MVC)

Conclusion

Appendix

Access Modifiers: Public vs Private

The `public` access modifier

How to access a public property

Access Modifiers: Public vs Private

The public access modifier

How to access a public property

The `public` access modifier