On 21/10/2018 21:17, Paul A Jungwirth wrote:
3. Build our own abstractions on top of ranges, and then use those to implement PERIOD-based features. This is the least clear option, and I imagine it would require a lot more design effort. Our range types are already a step in this direction. Does anyone think this approach has promise? If so I can start thinking about how we'd do it. I imagine we could use a lot of the ideas in [7]. ... [7] C. J. Date, Hugh Darwen, Nikos Lorentzos. Time and Relational Theory, Second Edition: Temporal Databases in the Relational Model and SQL. 2nd edition, 2014.
+1 on this approach. I think [7] got the model right. If we can implement SQL-standard PERIODs on top of it, then that's a bonus, but having sane, flexible, coherent set of range operators is more important to me.
What are we missing? It's been years since I read that book, but IIRC temporal joins is one thing, at least. What features do you have in mind?
- Heikki
