What debugging techniques can be used to identify and resolve errors in PHP scripts, especially related to database queries and form submissions?

One common debugging technique for identifying and resolving errors in PHP scripts related to database queries and form submissions is to use error reporting functions like error_reporting(E_ALL) and ini_set('display_errors', 1) to display any errors or warnings. Additionally, using functions like mysqli_error() to check for database query errors and var_dump() or print_r() to inspect form submission data can help pinpoint issues.

// Example of enabling error reporting and displaying errors
error_reporting(E_ALL);
ini_set('display_errors', 1);

// Example of checking for database query errors
$query = "SELECT * FROM users";
$result = mysqli_query($connection, $query);
if (!$result) {
    die("Database query failed: " . mysqli_error($connection));
}

// Example of inspecting form submission data
var_dump($_POST);