Login to existing website

I´m really impressed about bubble capabilities. I envision a lot of applications for my sites.
But i have a great constraint as I need to check de login against my DB which cannot be accesed from outside. I like to know if somebody has faced with a similar problem and how solved it.

Many thanks in advance.

Db was in different server like mysql/sql server? You need to access the db from bubble to implement login?

Many thanks for your quick response.
I cannot do that thing. I can build an API in my webiste in order to allow access from bubble.
Anybody has facing this issue?