Magento

Hello, I have 1 store with 5000 products how can I change the prices and upgrade them about 50% UP, Magento’s pricing rules only gives you the chance to make discounts and I don’t want to change them individually…

Do I have to tweak the database, using MySQL sentences?
I would like not to change anything on the database, my system is working fine and I’m afraid I make a mistake.

What do you think I should do?

Thanks