Prevent SQL Injection with PDO Prepared Statements

SQL Injection is a common attack on websites that use databases. It involves inserting malicious code into SQL statements that can harm your database or steal sensitive data. To prevent SQL Injection, it is important to use prepared statements.

What are Prepared Statements?

Prepared statements are a way to execute SQL statements that are precompiled by the database server. This means that the SQL statement and the user input are separated, and the user input is treated as a parameter instead of part of the SQL statement. This makes it impossible for an attacker to inject malicious code into the SQL statement.

How to Use Prepared Statements with PDO

PDO (PHP Data Objects) is a database abstraction layer that provides a consistent interface for accessing databases. To use prepared statements with PDO, you need to follow these steps:

1. Create a PDO object and connect to the database.
2. Prepare the SQL statement using the prepare() method.
3. Bind the parameters using the bindParam() or bindValue() method.
4. Execute the prepared statement using the execute() method.

<?php
// Step 1: create a PDO object and connect to the database
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');

// Step 2: prepare the SQL statement
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');

// Step 3: bind the parameters
$stmt->bindParam(':username', $username);

// Step 4: execute the prepared statement
$stmt->execute();
?>

As you can see, the username parameter is bound to the prepared statement using the bindParam() method. This ensures that the user input is treated as a parameter and not part of the SQL statement.

Conclusion

Using prepared statements with PDO is an effective way to prevent SQL Injection. By separating the SQL statement and the user input, you can ensure that your website is secure and your data is protected.