USE billing;

ALTER TABLE domains
ADD `reseller_id` int(11) unsigned NOT NULL,
ADD KEY `resellerid_idx` (`reseller_id`);

UPDATE domains d
INNER JOIN domain_resellers dr
ON d.id = dr.domain_id
SET d.reseller_id=dr.reseller_id;

ALTER TABLE domains
ADD CONSTRAINT `d_resellerid_ref` FOREIGN KEY (`reseller_id`) REFERENCES `resellers` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;