The only thing that needs a relational data store are reports. Operational data stores should only be concerned with their own domain and expose behaviors and events. There are exceptions, but if you’re building a complex system, monolithic architectures have a known lifetime while MSA’s tend to mitigate long term coderot.
It’s hard to see this until you’ve built domain driven micro service based systems properly.
It’s hard to see this until you’ve built domain driven micro service based systems properly.