text: ALTER TABLE `de_keywords_occurrences` ADD FOREIGN KEY ( `keyword_id` ) REFERENCES `ltv_keywords`.`de_keywords` (
  `keyword_id`
  ) ON DELETE CASCADE ON UPDATE CASCADE ;
  
  ALTER TABLE `de_keywords_occurrences` ADD FOREIGN KEY ( `file_id` ) REFERENCES `ltv_keywords`.`de_files` (
  `file_id`
  ) ON DELETE CASCADE ON UPDATE CASCADE ;
  
  
  ALTER TABLE `nl_keywords_occurrences` ADD FOREIGN KEY ( `keyword_id` ) REFERENCES `ltv_keywords`.`nl_keywords` (
  `keyword_id`
  ) ON DELETE CASCADE ON UPDATE CASCADE ;
  
  ALTER TABLE `nl_keywords_occurrences` ADD FOREIGN KEY ( `file_id` ) REFERENCES `ltv_keywords`.`nl_files` (
  `file_id`
  ) ON DELETE CASCADE ON UPDATE CASCADE ;