Do microservices use common databases?

Does microservices have their own database?

Yes. In a microservice architecture (MSA) services own their data. A service's database is part of its implementation and is private. The data is exposed indirectly via the service's API.

Do we need separate database for microservices?

You can use a single shared database with tables that owned by different microservices if your data is heavily related. Also in case you have strong requirements on data consistency and availiblty of a service.

Is it a good idea for microservices to share a common database?

I've seen folks refer to this idea in part, trivially, as “each microservice should own and control its own database and no two services should share a database.” The idea is sound: don't share a single database across services because then you run into conflicts like competing read/write patterns, data-model conflicts ...

Why each microservice has its own database?

It would allow you to pick the database technology which fits your Business requirement best in order to get the best performance or usage of it. For example some specific micro-service might have some Read-heavy operations with very complex filter options and a full text search requirement.