PHP数据库类不提交

I'm creating a php class what is able to handle my query's and db connections.

I've played around with it for a while and did some research, now I've created m When I use the class for something to handle it does not commit, but I'm not able to see why it doesn't I don't get any error's and my mysqli error handling is correct.

does anyone have a idea what's wrong with my script?

sql class:

class sql{

    function convertArrayReferences($arr){
        $refs = array();
        foreach($arr as $key => $value)
            $refs[$key] = &$arr[$key];
        return $refs;
    }
    function database($database, $query, $parameters){
        $result;
        $mysqli = new mysqli("****", "****", "****", $database);

        if(mysqli_connect_errno()){
            return "Connect failed: %s
 " . mysqli_connect_error();
        }

        if(!$stmt = $mysqli->prepare($query)){
            return $mysqli->error;
        }

        if(!$stmt->bind_param($this->convertArrayReferences($parameters))){
            return $mysqli->error;
        }

        if(!$stmt->bind_result($result)){
            return $mysqli->error;
        }

        if(!$stmt->execute()){
            return $mysqli->error;
        }

        $stmt->close();

        return $mysqli->error;
    }  
}

the bit of code where the function is called:

$execute = $sql->database("survivalTmpReg",
"INSERT INTO USERS (name, surname, email, username, password) VALUES (?, ?, ?, ?, ?)",
array("sssss", $name, $surname, $email, $username, $password));

if($execute){
    $message = REGISTER_MESSAGE;
}else{
    $message = $execute;
}

Statements are not automatically committed unless autocommit is turned on. On the first statement a transaction is created. Unless the transaction is not explicitly committed its changes will not be visible and eventually the transaction will be aborted by the system. MySQLi supports committing transactions using mysqli::commit.