Entity::getEntityIDByField PHP Method

    private static function getEntityIDByField($field, $value)
    {
        global $DB;
        $sql = "SELECT `id`\n              FROM `glpi_entities`\n              WHERE `" . $field . "` = '" . $value . "'";
        $result = $DB->query($sql);
        if ($DB->numrows($result) == 1) {
            return $DB->result($result, 0, "id");
        }
        return -1;
    }