What are some common mistakes to avoid when manipulating data in PHP files?

One common mistake to avoid when manipulating data in PHP files is not properly sanitizing user input, which can lead to security vulnerabilities such as SQL injection attacks. To solve this issue, always use prepared statements when interacting with databases to prevent malicious input from being executed as SQL commands. 

// Incorrect way without sanitizing user input
$user_input = $_POST['input'];
$query = "SELECT * FROM users WHERE username = '$user_input'";
$result = mysqli_query($connection, $query);

// Correct way with prepared statements
$user_input = $_POST['input'];
$query = "SELECT * FROM users WHERE username = ?";
$stmt = $connection->prepare($query);
$stmt->bind_param('s', $user_input);
$stmt->execute();
$result = $stmt->get_result();

Keywords

SQL injection XSS attacks data validation error handling file permissions

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