DO
$$
DECLARE
MAX INTEGER := 100;
i INTEGER := 0;
bookid INTEGER;
authorid INTEGER;
isLinked INTEGER;
BEGIN
    WHILE i < MAX LOOP
        SELECT get_or_create_book_and_friend(i::VARCHAR, i::VARCHAR) INTO bookid;

        SELECT update_or_create_author(i::VARCHAR, i::VARCHAR,(now () - (i*100) * INTERVAL '1 day')::DATE, (now () - (i*10) * INTERVAL '1 day')::DATE)   INTO authorid;

        EXECUTE 'select count(*) as isLinked from "AuthorBook" WHERE ("AuthorId" = $1) AND ("BookId" = $2)' INTO isLinked using bookid, authorid;
        IF isLinked = 0 THEN
        EXECUTE 'INSERT into "AuthorBook" ("AuthorId", "BookId") VALUES($1,$2)' using authorid, bookid;
        END IF;
        i := i + 1;
    END LOOP;
END;
$$