Why are there different databases in microservices?

Question

The microservices architecture enables using different kinds of data storing technologies for different services (aka applying polyglot persistence). Put simply, each development team can choose the persistence technology that suits the needs of their service best.

Why microservices have separate databases?

Creating a separate database for each service helps to enforce domain boundaries, but it's only one approach. There's nothing stopping you from having all your services share the same database. As long as your services behave and don't do unexpected things to data owned by other services, you'll be fine.

Should microservices have separate databases?

Each microservice should have its own database and should contain data relevant to that microservice itself. This will allow you to deploy individual services independently. Individual teams can now own the databases for the corresponding microservice.

Does each microservice have its own database?

The short answer is yes. However, before you start hyperventilating about the cost of all those extra Oracle licenses, lets first explore why it is essential to do this and then discuss what is meant by the term 'database'.

Expert · Answer