Lately I've seen some discussion in the Health IT field about separating or not the "data layer" from the "app layer". For some this is over complicating things, for others is a pretty basic architectural "good practice".
For me as a Software Architect, separating "data" from "apps" is a basic consideration for large Health IT projects (enterprise, regional, national and international).
So, what happens if we don't separate "data" and "apps" layers in large Health IT projects? 1. Vendor lock-in for years, 2. data blocking (can't access or share data), 3. innovation blocking (can't create new services over the existing data infrastructure).
And, what is needed to separate "data" and "apps" layers in Health IT? First we need to talk about infrastructure, which is NOT hardware! Is the information infrastructure, or how I prefer: INFOSTRUCTURE.
The INFOSTRUCTURE is the definition of how the information will be defined and managed: conceptual definition, use, purpose, misuse, versioning, constraints, binding to terminologies, and any other rule that applies to clinical/health/wellness information.
Note the definition of a process on how the information will be managed in the platform, is the first step to allow INTEROPERABILITY, which is key to provide any (distributed) service based on the INFOSTRUCTURE.
Yes, in Health IT, it's INFOSTRUCTURE first, INTEROPERABILITY second. As well as LOGICAL models and processes first, IMPLEMENTATION and TECHNOLOGY second.
For a successful health it project, the apis are not important, the programming language is not important, the development framework is not important. those are second class citizens. so, what's important?
1. People. 2. Processes. 3. Clear requirements (data and services). 4. Education. 5. INFOSTRUCTURE. Here is where you start worrying about the rest, but reaching 5 is a long run, since building a platform is not trivial.
Hope this helps to get some light on the topic of separating "data" from "apps" layers in Health IT. It's my humble opinion after some years in the field.