text: ALTER TABLE code_system DROP KEY code_system_id;
  DROP INDEX code_system_oid ON code_system;
  ALTER TABLE code_system ADD CONSTRAINT UK_7j0saojr9joix0quj9a65492x UNIQUE (code_system_oid);
  
  
  ALTER TABLE code_system_version DROP KEY code_system_version_id;
  
  ALTER TABLE value_set_category ADD CONSTRAINT UK_ei6kilxu5rvqu6h6tvsqgqtyh UNIQUE (code);
  DROP INDEX code ON value_set_category;
  
  ALTER TABLE value_set ADD CONSTRAINT UK_qqdh21ud433ry6ybr0mwnu6c2 UNIQUE (code);
  DROP INDEX code ON value_set;
  
  ALTER TABLE concept_code ADD CONSTRAINT UK_3qk6t75290ixvreggu1u1k9jw UNIQUE (code, fk_code_system_version_id);
  ALTER TABLE concept_code DROP KEY concept_code_id;
  DROP INDEX code ON concept_code;
  
  