DB_DataObjects - Update issues

Hi Just ran into a strange issue with Update that I have never encountered before, google yields no rewards. Code to execute: DB_DataObject::debugLevel(5);

        $sql1 = DB_DataObject::factory(TBL_SMS_CENTER_PENDING);
        $sql1->status = 'Suspended';
        $sql1->whereAdd("pending_id = '" . $sql->pending_id . "'");
        $sql1->update();
        print_r($sql1);

DB_DataObject::debugLevel(0); Error info is: DO_Sms_pending: CONNECT: Checking for database database_ in options DO_Sms_pending: CONNECT: USING CACHED CONNECTION DO_Sms_pending: ERROR: update: trying to perform an update without the key set, and argument to update is not DB_DATAOBJECT_WHEREADD_ONLY DO_Sms_pending Object ( [__table] => sms_pending [pending_id] => [data] => [priority] => [creation_date] => [revision_date] => [status] => Suspended [id] => [_DB_DataObject_version] => 1.8.4 [N] => 0 [_database_dsn] => [_database_dsn_md5] => c9f3ecac1f2cadc9e5c4095e36c2ad6b [_database] => admin [_query] => Array ( [condition] => WHERE ( pending_id = '1' ) [group_by] => [order_by] => [having] => [limit_start] => [limit_count] => [data_select] => * ) [_DB_resultid] => [_resultFields] => [_link_loaded] => [_join] => [_lastError] => ) Array ( [condition] => WHERE ( pending_id = '1' ) [group_by] => [order_by] => [having] => [limit_start] => [limit_count] => [data_select] => * ) The schema is set as: which is correct, pending_id is a primary key also. [sms_pending] pending_id = 129 data = 194 priority = 130 creation_date = 129 revision_date = 129 status = 130 [sms_pending__keys] pending_id = N Any help appreciated Cheers Ian