How can the use of HTML entities in database values impact data handling and presentation in web applications?

When HTML entities are stored in database values, they can impact data handling and presentation in web applications by causing issues such as displaying raw HTML code instead of rendered content, potential security vulnerabilities like cross-site scripting (XSS), and difficulties in manipulating or processing the data correctly. To prevent these issues, it is recommended to sanitize the data before storing it in the database and encode any special characters using functions like htmlentities() or htmlspecialchars() to ensure that the data is displayed correctly and securely in web applications.

// Sanitize and encode data before storing in the database
$unsafe_data = "<script>alert('XSS attack!');</script>";
$safe_data = htmlentities($unsafe_data);

// Store the sanitized data in the database
// Example query to insert data into a table
$query = "INSERT INTO table_name (column_name) VALUES ('$safe_data')";
// Execute the query using your preferred method (e.g., mysqli_query, PDO, etc.)