Re: [PROPOSAL] Temporal query processing with range types

On Sat, Jul 23, 2016 at 12:01 AM, David Fetter <david(at)fetter(dot)org> wrote:
> On Fri, Jul 22, 2016 at 01:15:17PM +0200, Anton Dignös wrote:
>> Hi hackers,
>>
>> we are a group of researches that work on temporal databases. Our
>> main focus is the processing of data with time intervals, such as
>> the range types in PostgreSQL.
>
> Thanks for your hard work so far!
>
> [Explanation and examples elided]
>
> To what extent, if any, are you attempting to follow the SQL:2011
> standard?
>
> http://cs.ulb.ac.be/public/_media/teaching/infoh415/tempfeaturessql2011.pdf

The querying in the SQL:2011 standard is based on simple SQL range restrictions
and period predicates (OVERLAP, PRECEDES, FOR SYSTEM_TIME AS OF, etc) that
functionality-wise in PostgreSQL are already covered by the operators and
functions on range types.

Operations such as aggregation, outer joins, set-operations on ranges
(mentioned in
Section 2.5 "Future directions" in the above paper) are not yet part of the
standard. These are the operations that require the adjustment (or splitting) of
ranges.

Best,

Anton