Everything's possible, but in your case you have to consider couple of things: store_id's can be found pretty much everywhere inside Magento data model which means that you need tons of queries to replace them all. Also there're constraints and foreign keys to consider so imagine the Boromir meme here (One does not simply update store_id-s). You need to disable those, make changes and make sure that they're restored. Magento uses cascades and stuff extensively so you need to put them back or risk serious database problems.
Tanel Raja
