I do think for some it might be easier to reason mechanically about dataflow through collection-oriented operators. But I suppose it's subjective.
clj-3df [1] to my understanding does something like Relic for datomic datalog using differential dataflow.
Disclaimer: I now work on XTDB [2], so datalog is somewhat now my day job.
He mentions it in various videos but these snippets are two quick finds:
In contrast, a system that only handles base data in terms of triples assumes that you have a perfect attribute-oriented information model figured out upfront. But given this is rarely the case users will want tools that help them to easily transform/migrate their data and schema over time. Ideally this takes the form of a declarative language that minimises the amount of code that needs to be written. However, without a compelling end-to-end transformation language figured out I think any alternative database systems with their alternative information models (triple-based or otherwise) will struggle to compare favourably with mainstream databases, where declarative data munging with SQL is considered valuable and routine.
Triples may well prove to be the best way to handle information in software over the long-term, but I'm not sure that the systems which currently work with triples are good enough or widespread enough to test that theory.
Curious, where do you think datomic and datalog fall short (assuming one is using clojure and datomic's performance is tolerable)? By "perfect attribute-oriented model" I assume you are referring to the database's information model and support for that model, not to domain modeling with triples. Triples and relations are equally flexible but which models require more effort to maintain and transform along side with your application?
I think Hickey's point is that the structurally rigid nature of relations and stuff like arbitrary join tables needed to created many-to-many relations is that they get hard-coded throughout your application making your applications very hard to change over time, forcing you to put extreme effort to provide a set of logical views to isolate the application from the physical structural decisions. He says 'the more structural components(tables/intersection tables and having to name them(places)) you have in your model the more rigidity you get in your applications, but as you mentioned, triples haven't prove themselves.
I'm not experienced enough to understand all the tradeoffs here and can't tell if Hickey is wearing a salesman hat ;)
Of course, databases like postgres would be my first choice for most projects (even if using clojure which I like but is still a hard sell for webapps), as you said, they have too much going for them (flexibility of relational algebra, SQL, they are well understood, widespread, great ahd well supported implementations, etc..)
> provide a set of logical views to isolate the application from the physical structural decisions
To me this feels like the holy grail for what people really want from databases (beyond the basics of transactions/durability), and triples definitely still hold promise as a helpful abstraction. However I suspect Incremental View Maintenance (as Relic discusses) has a potentially even bigger role to play here.
Of course you can have dev time scratch environments to play with stuff without to support
[1] https://docs.datomic.com/on-prem/best-practices.html?search=...
[2] https://docs.datomic.com/on-prem/best-practices.html?search=...