How can SQL injection vulnerabilities be prevented when using external data in PHP scripts?

SQL injection vulnerabilities can be prevented in PHP scripts by using prepared statements with parameterized queries. This method ensures that user input is treated as data rather than executable code, thus preventing malicious SQL queries from being injected into the database. 

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

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

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

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

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

Keywords

SQL injection PHP scripts external data prepared statements parameterized queries

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