One of the fundamental aspects of microservice architecture is data ownership. Encapsulation of the data and logic prevents the tight coupling of services. Since they only expose information via public interfaces (like stable REST API) and hide inner implementation details of data storage, they can evolve their schema independently of one another.

A microservice should be an autonomous unit that can fulfill most of its assignments with its own data. It can also ask other microservices for missing pieces of information required to complete its tasks and, optionally, store them as a denormalized copy in its storage.