Constructors & Destructors in PHP

Introduction

What You’ll Learn

In this tutorial, you will learn:

• what constructors are
• how __construct() works
• what destructors are
• how __destruct() works
• real-world use cases of both methods

👉 Understanding constructors and destructors is an important step toward writing professional OOP code in PHP.

What is a Constructor in PHP?

A constructor is a special method that is automatically called when an object is created.

In PHP, a constructor is defined using the __construct() method.

It is mainly used to:

• Initialize properties
• Set default values
• Prepare the object for use

Why Do We Need Constructors?

Without constructors, you must manually set values after creating an object.

With constructors:

• Code becomes cleaner
• Object is ready immediately
• Fewer chances of mistakes
• Initialize object properties
• Ensure required values are provided

Constructor Example (Basic)

<?php
class User {
    public $name;

    public function __construct() {
        $this->name = "Guest";
    }
}
?>

Explanation:

• __construct() runs automatically
• $name is set as soon as object is created

Example Without Constructor

<?php
class Car {
    public $brand;
}$car1 = new Car();
$car1->brand = "Toyota";
?>

Here, we assign the property manually after creating the object.

Example With Constructor

<?php
class Car {
    public $brand;    public function __construct($brand) {
        $this->brand = $brand;
    }
}$car1 = new Car("Toyota");
?>

Now the object is initialized immediately when created.

Creating Object with Constructor

<?php
$user = new User();
echo $user->name;
?>

Output:

Guest

Constructor with Parameters

You can pass values while creating the object.

<?php
class User {
    public $name;
    public $email;

    public function __construct($name, $email) {
        $this->name = $name;
        $this->email = $email;
    }
}
?>

Passing Values to Constructor

<?php
$user = new User("Divyesh", "div@example.com");

echo $user->name;
echo $user->email;
?>

Now the object is initialized immediately with values.

Multiple Constructors? (Important Note)

PHP does NOT support multiple constructors.

But you can simulate this by:

• Using optional parameters
• Using default values

public function __construct($name = "Guest") {
    $this->name = $name;
}

What is a Destructor in PHP?

A destructor is a special method that runs when an object is destroyed.

It is defined using __destruct().

Destructors are used to:

• Close database connections
• Free resources
• Perform cleanup tasks

Destructor Example

<?php
class Database {
    public function __construct() {
        echo "Connection opened";
    }

    public function __destruct() {
        echo "Connection closed";
    }
}
?>

When is Destructor Called?

Destructor is called when:

• Script execution ends
• Object is unset using unset()

<?php
$db = new Database();
unset($db);
?>

Should Beginners Use Destructors?

Destructors are:

• Not used frequently
• Helpful in advanced applications
• Common in database and file handling classes

Understanding them is enough at this stage.

Real-World Use Case

In real projects:

• Constructor → opens DB connection
• Destructor → closes DB connection

This ensures proper resource management.

Key Differences Between Constructor and Destructor

Common Mistakes Beginners Make

• Misspelling __construct or __destruct
• Forgetting the double underscore
• Trying to manually call constructors
• Passing wrong parameters
• Not understanding when destructor runs

Remember: these methods run automatically.

FAQs

Practical Task

Create a class named User:

• Add a constructor that accepts a username
• Display a message when the object is created
• Add a destructor that prints a message when the object is destroyed

Observe when each method runs during script execution.

Conclusion

Constructors and destructors are important parts of Object-Oriented Programming in PHP because they help manage an object’s lifecycle automatically.

A constructor prepares the object when it is created, while a destructor handles cleanup when the object is no longer needed.

Using constructors makes your code cleaner and safer by ensuring objects are initialized properly from the beginning. Destructors help maintain better resource management in larger applications.

These concepts are commonly used in real-world PHP projects like database handling, file management, and framework development.

Once you understand constructors and destructors, learning advanced OOP concepts becomes much easier.

👉 Mastering these small concepts helps you write more professional and scalable PHP code.

In the next tutorial, we’ll learn about Access Modifiers in PHP (public, private, protected).