Prisma

For example, from mongo and MySQL at the same time.

Although I am also new to it but I have some concept in it. For example you have one web application like facebook. You want to store the login/signup details and other logic in mysql and on the other side you want to create the mongodb for saving post details and some logic. Then for both of these you have to create separate servers. I do not know about combining     both mysql and mongodb to one.

While using multiple Databases can make sense, I think with your example you should just stick with MySQL. Or do you have any reason to use MongoDB?

It's currently not possible to use two databases, but I think it's planned (although that can take a lot of time)

You could create two separate Prisma servers, one for MongoDB and one for MySQL of course, but you don't get relations between those obviously

I think that would be useful for applications like Facebook's example.