Are there any common pitfalls to avoid when using PHP to interact with a database for form population?

One common pitfall to avoid when using PHP to interact with a database for form population is not properly sanitizing user input, which can leave your application vulnerable to SQL injection attacks. To solve this issue, always use prepared statements or parameterized queries to securely interact with the database and prevent malicious input from affecting your queries. 

// Connect to the database
$pdo = new PDO('mysql:host=localhost;dbname=my_database', 'username', 'password');

// Prepare a 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(PDO::FETCH_ASSOC);

// Populate the form fields with the retrieved data
foreach ($results as $row) {
    echo '<input type="text" name="username" value="' . htmlspecialchars($row['username']) . '">';
}

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