Transaction management in PHP - Mini Project: Build & Apply

Transaction management

📖 Scenario: You are building a simple PHP script to manage a bank account transaction. You want to make sure that money is only withdrawn if there is enough balance, and if something goes wrong, the transaction should be canceled.

🎯 Goal: Create a PHP script that uses transaction management to safely withdraw money from a bank account balance stored in a variable.

📋 What You'll Learn

Create a variable $balance with the initial amount of 1000

Create a variable $withdraw with the amount to withdraw, 300

Use transaction management with try and catch blocks

Check if $balance is enough for the withdrawal

If enough, subtract $withdraw from $balance

If not enough, throw an exception with message 'Insufficient funds'

Print the final balance or the error message

💡 Why This Matters

🌍 Real World

Transaction management is important in banking and shopping websites to keep data safe and consistent.

💼 Career

Understanding how to use transactions and error handling is a key skill for backend developers working with databases.

1

Set up initial balance and withdrawal amount

Create a variable called $balance and set it to 1000. Then create a variable called $withdraw and set it to 300.

PHP

$balance = 1000;
$withdraw = 300;
# Your code here

Need a hint?

Use simple variable assignment like $balance = 1000;

2

Start transaction with try block

Add a try block to start the transaction management. Inside it, write a comment // Transaction starts.

PHP

<?php
$balance = 1000;
$withdraw = 300;

try {
    // Transaction starts
    # Your code here
}

Need a hint?

Use try { } to start the transaction block.

3

Check balance and update inside try block

Inside the try block, write an if statement to check if $balance is greater than or equal to $withdraw. If yes, subtract $withdraw from $balance. Otherwise, throw a new Exception with the message 'Insufficient funds'. Add a catch block to catch Exception as $e.

PHP

= $withdraw) {
        // Your code here
    } else {
        // Your code here
    }
} catch (Exception $e) {
    // Your code here
}

Need a hint?

Use throw new Exception('Insufficient funds'); to stop the transaction if balance is low.

4

Print the final balance or error message

After the try-catch block, write an if statement to check if $error is set. If yes, print 'Error: ' followed by $error. Otherwise, print 'Final balance: ' followed by $balance.

PHP

= $withdraw) {
        $balance -= $withdraw;
    } else {
        throw new Exception('Insufficient funds');
    }
} catch (Exception $e) {
    $error = $e->getMessage();
}

// Your code here

Need a hint?

Use print("Final balance: $balance\n"); to show the result.