Rant about Prestashop's Database

[archproject]

Really I can't help ranting about this topic..... Prestashop team is not doing a great job in cleaning up the mysql database for example ... when I create combination from the combination generator ... it generates well but then when I want to re-generate the combinations ... it still shows the old combinations in the database and then ... this will eventually make my database bigger and bulkier .... just because for one product i have about 200 -300 combinations... anyway .. another case is when I update my carrier it just creates another row in the tables.... and not deleting the old one the effect is having another ID for the updated carrier which already exists.....

maybe the prestashop team has some functionality built in to this maybe I just don't understand but can somebody explain to me why is this so for the database...