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I've been reading Snodgrass's "Developing Time-Oriented Database Applications in SQL" and I'm consulting other documents as well, but I'm willing to find more modern stuff about time-oriented design for databases and the tools available for that in Postgresql.

Also found this document.

I would be grateful just with any link or advice on the topic discussing:

  • Temporal and bitemporal tables
  • Coalescing
  • Validity, applicability time, transaction time
  • Primary keys, constraints and referential integrity in temporal DBs
  • Design and good design practices for temporal DBs
  • Native Postgresql solutions for all of the above

I have still more to read from the book and I've discovered some SQL:2011 issues about time, but they'are not implemented in Postgresql.

There's still some things I don't know how to handle or understand, for example, I found this article mentioning this:

CREATE TABLE travel_log (
 id serial PRIMARY KEY,
 name varchar(255),
 travel_range daterange,
 EXCLUDE USING gist (travel_range WITH &&)
); 

which I understand it could be useful for not having overlapping rows, but even though I searched the Postgresql docs, I only read what the EXCLUDE does and that gist is just some type of INDEX, but I can't figure out which kind of syntax is the "WITH &&" thing and what does it provide.

I would be happy just having resources where I could learn about all this. Thank you very much.

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The WITH keyword defines the operator which is used to test for "equality" between two rows.

A regular unique index is just a special case of an exclusion constraint. If you were to define a "normal" unique constraint using an exclusion constraint, you would use = as the operator, e.g: exclude using btree (id with =) instead of unique (id)


The && for range types is the "overlaps" operator which tests if two ranges, well, overlap.

e.g.

daterange('2019-01-01', '2019-02-21') && daterange('2019-02-08', '2019-03-01') 

returns true (as the ranges overlap)

while

daterange('2019-01-01', '2019-02-21') && daterange('2019-02-22', '2019-03-01') 

will return false as there is no overlap.

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