ALTER TABLE `Keyword` DROP `identifier`; CREATE TABLE `Keyword_researcharea` ( `Keyword_id` bigint(20) NOT NULL, `researchAreas_id` bigint(20) NOT NULL, KEY `FKF8C66F5E98ED461` (`Keyword_id`), KEY `FKF8C66F5E6F20ECBC` (`researchAreas_id`), CONSTRAINT `FKF8C66F5E6F20ECBC` FOREIGN KEY (`researchAreas_id`) REFERENCES `researcharea` (`id`), CONSTRAINT `FKF8C66F5E98ED461` FOREIGN KEY (`Keyword_id`) REFERENCES `Keyword` (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- add this to project idea ALTER TABLE `projectIdea` ADD `researchArea_id` bigint(20) DEFAULT NULL;