text: CREATE TABLE issue_assignation
  (
        issue_id    $ISSUE_ID_TYPE                      NOT NULL
      , assigned_at $ISSUE_ASSIGNATION_ASSIGNED_AT_TYPE NOT NULL
      , assigned_id $PARTY_ID_TYPE                      NOT NULL
      , assignee_id $PARTY_ID_TYPE                      NOT NULL
      , CONSTRAINT fk_issue_assignation_assignee_id
          FOREIGN KEY (assignee_id) REFERENCES party (id)
              ON DELETE RESTRICT
              ON UPDATE CASCADE
      , CONSTRAINT fk_issue_assignation_assigned_id
          FOREIGN KEY (assigned_id) REFERENCES party (id)
              ON DELETE RESTRICT
              ON UPDATE CASCADE
      , CONSTRAINT pk_issue_assignation
          PRIMARY KEY (issue_id, assigned_at)
  ) ENGINE=InnoDB
  ;
  