Slope-One recommender implementation using mysql stored procedure - mysql

Question

I am trying to implement Slop-One recommender using mysql stored procedure, the query runs okay and doesn't give any error. But it is not inserting/updating the 'dev' table.
The structure of tables are:
rating (user_id, article_id, rating_value, date)
dev (article1_id, article2_id, count, sum)
The 'dev' table has joint primary key (article1_id, article2_id). The sql for my procedure is as follows:
DELIMITER $$
CREATE PROCEDURE update_matrix(IN user INT(11), IN article INT(11), IN rating TINYINT(1))
BEGIN
DECLARE article_id2 INT(11);
DECLARE rating_diff TINYINT(1);
DECLARE done TINYINT(1) DEFAULT 0;
DECLARE mycursor CURSOR FOR
SELECT DISTINCT article_id, (rating - rating_value)
FROM rating
WHERE user_id = user AND article_id != article;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN mycursor;
FETCH mycursor INTO article_id2, rating_diff;
WHILE(!done) DO
INSERT INTO dev (`article1_id`, `article2_id`, `count`, `sum`)
VALUES (article, article_id2, 1, rating_diff)
ON DUPLICATE KEY UPDATE count = count + 1, sum = sum + rating_diff;
INSERT INTO dev (`article1_id`, `article2_id`, `count`, `sum`)
VALUES (article_id2, article, 1, -rating_diff)
ON DUPLICATE KEY UPDATE count = count + 1, sum = sum - rating_diff;
FETCH mycursor INTO article_id2, rating_diff;
END WHILE;
CLOSE mycursor;
END$$
DELIMITER ;