By most definitions of microservices I've heard there's a 1:many relationship between microservices:datastores. Multiple microservices can't talk to the same database. For example:

> While monolithic applications prefer a single logical database for persistant data, enterprises often prefer a single database across a range of applications... Microservices prefer letting each service manage its own database, either different instances of the same database technology, or entirely different database systems https://martinfowler.com/articles/microservices.html

Not to say that pattern can't be successfully implemented, just that it wouldn't be considered microservices. It sounds like you're describing a three-tier architecture: https://en.wikipedia.org/wiki/Multitier_architecture#Three-t...