How can PHP be used to validate form input before executing database queries to prevent errors?

To prevent errors when executing database queries, it is essential to validate form input before interacting with the database. This can be done by checking for the presence of required fields, validating input formats, and sanitizing input to prevent SQL injection attacks. By validating form input before executing database queries, you can ensure that only safe and properly formatted data is sent to the database, minimizing the risk of errors. 

// Validate form input before executing database queries
if(isset($_POST['submit'])) {
    $name = $_POST['name'];
    $email = $_POST['email'];
    
    // Validate required fields
    if(empty($name) || empty($email)) {
        echo "Please fill out all required fields.";
        return;
    }
    
    // Validate email format
    if(!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        echo "Invalid email format.";
        return;
    }
    
    // Sanitize input to prevent SQL injection
    $name = mysqli_real_escape_string($conn, $name);
    $email = mysqli_real_escape_string($conn, $email);
    
    // Execute database query with validated input
    $query = "INSERT INTO users (name, email) VALUES ('$name', '$email')";
    mysqli_query($conn, $query);
    
    echo "Data successfully submitted to the database.";
}

Keywords

PHP form validation database queries error prevention input validation

Related Questions