How do I activate/enable the caches in Magento manually?

Hello,

I disactivated/disabled the caches with the Admin panel, to add some modifications to my website. Unfortunately when I finished, I forgot to reactivate the caches.
Now my website is no more reachable. My browser says that it is due to the fact that the caches are disabled/refused.

Isn't it possible to activate the caches manually? Maybe by modifying the value of rows in a table of the database?

Thanks a lot for your help and answers.