<?php

/*
 * Should I be doing this?
 */

class Service {

    private function connectLicenseDatabase() {
        //Some lines of code to connect to the license database
        return $dbh;
    }

    private function getUserDetails($order_id) {
        //Some lines of code to get user datails
        return $user_details
    }

    private function getPaidInvoiceFromOrder($order_id) {
        //Some lines of code to get the invoice id
        return $invoice_id
    }

    public function addLicense($params = array()) {

        $userDetails = $this->getUserDetails($params['order_id']);

        $bindings = array_merge($userDetails, $params);

        $bindings['invoice_id'] = $this->getPaidInvoiceFromOrder($params['order_id']);

        $dbh = $this->connectLicenseDatabase();

        $qry = $dbh->prepare(...);

        $qry->execute($bindings);

        return $qry->fetchAll(...);
    }

}

/*
 * Instead of this
 */

class Service {

    public function addLicense($params = array()) {
        //Some lines of code to get user details
        $userDetails = array(...);
        //Some lines of code to get the invoice id
        $invoice_id = ...;
        //Some lines of code to connect to the DB
        $dbh = ...;

        $bindings = array_merge($userDetails, $params);

        $qry = $dbh->prepare(...);

        $qry->execute($bindings);

        return $qry->fetchAll(...);
    }

}

?>