What are the best practices for handling user input data and preventing SQL injections in PHP applications?

To prevent SQL injections in PHP applications, it is crucial to sanitize and validate user input data before using it in SQL queries. One of the best practices is to use prepared statements with parameterized queries, which separate SQL code from user input data, preventing malicious SQL injections. 

// Example of using prepared statements to prevent SQL injections
$pdo = new PDO("mysql:host=localhost;dbname=mydatabase", "username", "password");

// Sanitize and validate user input data
$userInput = $_POST['user_input'];
$userInput = filter_var($userInput, FILTER_SANITIZE_STRING);

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

// Bind the sanitized user input to the placeholder
$stmt->bindParam(':username', $userInput);

// Execute the prepared statement
$stmt->execute();

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

Keywords

validation prepared statements parameterized queries escaping input filtering

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