Re: SQL:2011 PERIODS vs Postgres Ranges?

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