OOPs Concepts in PHP: Go From Chaos to Clean Code in 2025

Learning OOPs concepts in PHP is a vital aspect of mastering the art of programming. Whether it is to maintain the codebases, debug errors, scale applications, or ensure modularity, implementing OOPs concepts in PHP can enhance the quality of the entire development process.

Object-oriented programming lets you structure your code into reusable and modular components, allowing you to easily manage changes as your project evolves with respect to market trends or needs. It doesn’t matter if you are creating an enterprise-grade application or a small dynamic platform; applying OOPs concepts in PHP can open the doors for you to write efficient, scalable, and future-ready code scripts.

In this blog, we will focus on understanding the core OOPs concepts in PHP with practical code examples. So, let’s begin.

Understanding OOPs Concepts in PHP: What It Is and Why It Matters

Object-Oriented Programming (OOP) in PHP is a programming methodology specifically designed to organize code into objects and classes. As a result, developers have the flexibility to simulate real-world entities and their behavior within a software application. It promotes structure, modularity, and reusability of the code, making it less chaotic to handle and more flexible to scale.    

With the help of OOPs concepts in PHP like inheritance, encapsulation, polymorphism, and abstraction, you can significantly minimize redundant tasks, leading to optimal efficiency and productivity. The applications that were designed and developed by using long procedural PHP scripts can now be created by implementing a clean architectural-style OOP method.

Key OOPs Concepts in PHP

These are the following OOPs concepts in PHP:

1. Classes and Objects

Classes in PHP are the entities that act like a blueprint or template for creating objects. These are responsible for including the properties to store the data and methods for performing programming actions.

Whereas an object is an instance of a class, which represents a fixed entity created by using the class as a blueprint. These objects have their own state and behavior associated with them.

Example:

Imagine a Car class entity having objects like Car1 or Car2. Here, these two (2) objects can have multiple properties like color, model, mileage, and methods like drive() and brake().

2. Properties and Methods

Properties are variables within a class that store information about the object. On the other hand, methods are functions defined inside a class, which describe the actions performed by an object. 

Together, properties and methods specify the entire behavior and characteristics of an object. The accessibility of properties and methods can differ based on visibility levels — public, private, or protected — to ensure data security and control.

Example:

A Student class entity can have properties like name, roll number, marks, and methods such as study(), submitAssignment (), and viewResult().

3. Constructors and Destructors

In PHP, a constructor is a special function that operates automatically when a new object is created. The primary purpose of this special function is to initialize property values and perform the setup tasks required for the object. Constructors are defined using the __construct() method. 

A destructor is a type of function that is invoked at the time of object destruction (in simple terms, when an object goes out of scope). Destructors are defined using the _destruct() method. This method or function is mainly used to clean up resources, such as freeing memory space or blocking database connections.

Example:

To gain control over an object’s lifecycle, these two (2) methods are used. Like in the case of a Car class entity, you can use a constructor method to set its initial properties, like color, model, or company name, for each Car object. At the same time, you can implement the destructor function to log when the object gets removed from the memory.

4. Inheritance

Inheritance is one of the fundamental OOPs concepts in PHP, which enables a child class to inherit properties and methods from its parent or ancestor classes. This approach of absorbing properties enhances code reusability and prevents redundant and monotonous tasks. 

This working mechanism allows he developers to establish hierarchical relationships between classes. In PHP, a child class can inherit the properties from its parent class by using the extends keyword.

Example:

A Vehicle parent class can have properties like speed, fuelType, and capacity, and it can also include start() and stop() as its methods or functions. In this case, child classes Bus and Bike can inherit these base properties and methods in addition to their own specific characteristics and features, such as model or color.

5. Polymorphism

Polymorphism is a crucial OOPs concept in PHP, specifically implemented to allow objects of different classes to be treated as objects of a common parent class. This will enable methods or functions to behave or respond differently according to their object type. 

Incorporating polymorphism gives your code flexibility to manage multiple object types without any performance issues. But like other programming languages, such as Java or C++, PHP doesn’t support method overloading. In PHP, polymorphism is implemented through method overriding, where a parent class method is redefined in a child class to manipulate its behavior.

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Example:

Let’s say there are two different types of vehicles: a car and a bike. We can create two separate classes for them: the Car class and the Bike Class. Both classes can inherit a Vehicle parent class with a start() function. While observing that this function exists in the parent class, each class can implement its own unique version of start().

6. Abstraction

Abstraction is one of the vital OOPs concepts in PHP, which involves hiding the complex implementation details of a class and showcasing only those features to the users that are essential from the app usability perspective. It is implemented by using an abstract class or interface in PHP. 

The main objective of Abstraction is to hide the data and allow the developers to define object operations without exposing its internal workflow, leading to more efficient code interaction and modularity.

Example:

Imagine an Insurance Firm, where an abstract InsurancePolicy class can define an abstract function calculatePremium(). Concrete classes like HealthInsurance and CarInsurance will now implement this particular method to conduct insurance operations. Still, the users are not required to know the internal working mechanism of how premiums are calculated.

7. Encapsulation

Encapsulation is another OOPs concept in PHP, which is a programming principle of preventing direct access to an object’s properties and methods. The reason behind this approach is to expose only those parts of the code that are publicly accessible to end users. 

Through the getters and setters, it protects sensitive data from unauthorized activities and ensures a security layer is added to maintain data consistency, integrity, and reliability.

Example:

The encapsulation process is necessary to hide implementation details and maintain a clear interface, promoting interactivity with the objects. Imagine a BankAccount class with a private balance property that can’t be accessed directly. In this case, the class provides functions or methods like deposit() and getBalance() to update and retrieve the balance safely and securely.

Let’s now move into a real-world example where we will cumulatively observe and learn about all the above OOPs Concepts in PHP, helping you develop a practical understanding of how these concepts are implemented to create an impact.

Real-World Code Example of OOPs Concepts in PHP

This PHP code is designed to create food orders, enabling users to add multiple food items along with their prices. After the food items are added, this program calculates the total amount, including the delivery fee, and displays the final amount when the order is completed.

<?php

// Abstraction: Abstract class for Orders

abstract class Order {

    protected $items = []; // Encapsulation

    public function addItem($item, $price) {

        $this->items[$item] = $price;

    }
    abstract public function calculateTotal(); // Must be implemented by child

}

// Inheritance: OnlineOrder inherits from Order

class OnlineOrder extends Order {

    private $deliveryFee;

    public function __construct($fee) { // Constructor

        $this->deliveryFee = $fee;

    }

    public function calculateTotal() { // Polymorphism

        $total = array_sum($this->items) + $this->deliveryFee;

        return $total;
    }

    public function __destruct() { // Destructor

        echo "Order completed. Total: $" . $this->calculateTotal() . "\n";

    }

}

// Classes & Objects: Using the OnlineOrder

$order = new OnlineOrder(5); // $5 delivery fee

$order->addItem("Burger", 10);

$order->addItem("Fries", 3);

$order->addItem("Coke", 2);

echo "Total without delivery: $" . array_sum($order->items) . "\n";

?>

Explanation:

• In this food ordering program, the Order class is basically acting as a template and is responsible for instructing every order that it must possess a way to calculate the total, which is known as abstraction.

• As you can see, there is a list of food items, $items, which is protected. To change it, you have to carefully implement the addItem() method, which is known as encapsulation.   

• Here, the OnlineOrder class extends the Order class by inheriting its properties, and $order is the actual instance of that class, highlighting the respective classes and objects.     

• Now, when anyone creates a new order, the __construct() function sets the delivery fee, and when the order is completed, the __destruct() method automatically returns the total amount as the output.

• Here, as the inheritance is also involved, the OnlineOrder class overrides the calculateTotal() method from the Order class to ensure it behaves differently according to the online orders, which demonstrates the polymorphism process.

Best Practices for Writing Clean OOPs Code in PHP

To ensure good OOP practices, developers should follow key guidelines that help maintain code quality, improve performance, and build robust applications. Some essential practices include:

• Meaningful names – classes and methods should be self-explanatory.

• Single Responsibility – each class should do one thing.

• Encapsulation – use private/protected with getters/setters.

• Follow the DRY (Don’t Repeat Yourself) Principle– avoid repeating code.

• Type declarations – ensure consistent data.

• Dependency injection – keep code flexible and testable.

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Conclusion

In conclusion, if you are willing to build a strong command of PHP, you must master all the OOPs concepts in PHP, along with gaining hands-on experience in applying those concepts while developing real-world applications. From an interview standpoint, most tech companies always expect a sound knowledge of OOPs from the candidates. So, try to delve deep into these concepts and know how they can help in transforming real-world problems into actual software solutions.

FAQs

Why are OOPs Concepts in PHP important?

To organize code using classes and objects for modular, reusable, and maintainable programs.

Why use inheritance, polymorphism, and encapsulation?

Inheritance reuses code, polymorphism allows flexible behavior, and encapsulation protects data. Altogether, they make code reusable, flexible, secure, and easier to maintain.

What are the key best practices for clean OOP code?

Use meaningful names, keep classes focused, encapsulate data, use abstraction, and follow the DRY principle.