Invalidate cache from database

Hello!
I have a lot of websites on one hosting with one mysql server.
There will be a mass changing of content through databases of those websites.
On the websites where changes will be made I need to refresh cache.
Is it somehow possible to force refresh cache by changing some parameter in some table in database of a website?

And another question. Will pages refreshes after a while, or the cache is eternal?
[ed. note: holden321 last edited this post 8 years, 1 month ago.]

MODX Evolution 1.2.1-beta

Manually deleting all files in the cache directory is probably the most reliable way to do it.

Yes, I have done that by a script on the hosting server (fortunately all the websites are on one web server).
Another way is clicking the button "clear the cache" from manager by http request (you need to login first to get cookies) but the aforementioned way is better in my case.