If I can create an Order class that holds a list of LineItems and I can impose a minimum order amount rule over that list, I can write a unit test for that that needs nothing but Java and a ms to execute. Why should I complicate that?

Well, are you going to store it or not? If not, as you so eloquently put: en.wikipedia.org/wiki/Straw_…

Yes. But thats my point: why would you conflate the two? You argued separation of concerns yourself, didn’t you? You asked for a reason why one’d not use the relation model as primary. One answer: because it’s simpler to use a different one, not tied to a storage technology.

Admittedly, you could argue it would be even better to specify everything in a meta language, e.g. some kind of DSL, so that you’re not tied to Java

Sure, if you’re in a context where building DSLs is (economically) feasible. For mere mortals, it boils down to some arbitrary, general purpose programming language.

I’m not seriously suggesting that. I’m merely pointing out that you see no problem with a dependency on Java/the JVM, but do with one on SQL/an RDBMS.

I am surprised you actually derive *that* from the tweet. It was not my point at all.

I derived it from the “not tied to a storage technology”

Which Java – and any other general purpose programming language – obviously is not? 🤔 Whenever we built an app, there will be code. I'd just like to stick to *that* for fundamental rule implementations rather than rely on some specific downstream tech.

I am pretty surprised I have to defend an "There are other options with other tradeoffs" against a trollish "Just always use X. Why bother with anything else?". But I guess I should've know where this is going when I originally replied. 🤷‍♂️