mysqli_query插入localhost，表不更新

I am trying to insert user details into a table i have created using phpmyadmin on a local host server.

the connections are fine and the first user gets inserted into the table no problem.

when I attempt to add another user it does not show in the table in phpmyadmin nor do i get any kind of error.

I have a feeling its something to do with the table configuration but i cannot find any info on this, can something please help.

The Insert code

$result = db_query("INSERT INTO registration_list (first_name, last_name, student_number, email, activation_code, status, time_created, time_updated)
    VALUES (
            '$fname',
            '$sname',
            '$studentNo',
            '$email',
            '$code',
            'awaiting approval',
            now(),
            now()
        )");

The connection

function db_connect(){

static $connection;

if(!isset($connection)) {
    $connection = connectLocalHost($connection);
}
if($connection === false) {
    return db_error();
}
return $connection;
}

function db_query($query) {
// Connect to the database
$connection = db_connect();
// Query the database
$result = mysqli_query($connection,$query);
return $result;
}