Reads and Writes don’t have to live in the same database, data model or even the same service. Let us discuss CQRS

no separation

one service that does read/write

partial separation

You can keep one service but backend have multiple connections with different users same database

full separation

Read services / write services

two databases OLAP / OLTP

Pros

scalability

security

Cons

complex and very hard to follow, what we see with microservices..

resources

https://martinfowler.com/bliki/CQRS.html

http://codebetter.com/gregyoung/2010/02/16/cqrs-task-based-uis-event-sourcing-agh/