ALTER TABLE `event_wait_list`
ADD `event_id` INT(10) NULL,
ADD KEY `fk_event_id` (`event_id`),
ADD CONSTRAINT `fk_event_id` FOREIGN KEY (`event_id`) REFERENCES `event` (`event_id`) ON UPDATE CASCADE;

ALTER TABLE `event_wait_list_deregistration`
ADD `event_id` INT(10) NULL,
ADD KEY `fk_event_wait_list_id` (`event_id`),
ADD CONSTRAINT `fk_event_wait_list_id` FOREIGN KEY (`event_id`) REFERENCES `event` (`event_id`) ON UPDATE CASCADE;

ALTER TABLE `event_registration`
ADD `event_id` INT(10) NULL,
ADD KEY `fk_event_registration_id` (`event_id`),
ADD CONSTRAINT `fk_event_registration_id` FOREIGN KEY (`event_id`) REFERENCES `event` (`event_id`) ON UPDATE CASCADE;

ALTER TABLE `event_schedule_email_status`
ADD `event_id` INT(10) NULL,
ADD KEY `fk_event_schedule_email_status_id` (`event_id`),
ADD CONSTRAINT `fk_event_schedule_email_status_id` FOREIGN KEY (`event_id`) REFERENCES `event` (`event_id`) ON UPDATE CASCADE;

ALTER TABLE `event_email_template_mapping_by_event_schedule`
ADD `event_id` INT(10) NULL,
ADD KEY `fk_event_email_template_mapping_by_event_schedule_id` (`event_id`),
ADD CONSTRAINT `fk_event_email_template_mapping_by_event_schedule_id` FOREIGN KEY (`event_id`) REFERENCES `event` (`event_id`) ON UPDATE CASCADE;