What are the best practices for handling user input in PHP to prevent SQL injection vulnerabilities and ensure data security?

To prevent SQL injection vulnerabilities in PHP, it is crucial to sanitize user input before using it in database queries. One common approach is to use prepared statements with parameterized queries, which separate SQL code from user input. Additionally, input validation can help ensure that only expected data types and formats are accepted, further reducing the risk of injection attacks. 

// Example of using prepared statements to prevent SQL injection

// Establish a database connection
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');

// Prepare a SQL statement with a placeholder for user input
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');

// Bind the user input to the placeholder
$stmt->bindParam(':username', $_POST['username']);

// Execute the query
$stmt->execute();

// Fetch the results
$results = $stmt->fetchAll();

Keywords

SQL injection user input validation prepared statements PDO data sanitization

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