I just found out that this is a feature introduced in PostgreSQL 10,
back in 2017.
Besides this being the standard way to define an “auto incremental
column” introduced in SQL:2003[0], called “identity columns”, in
PostgreSQL the new syntax has the following pros, according to [1]:
* No need to explicitly grant usage on the generated sequence.
* Can restart the sequence with only the name of the table and column;
no need to know the sequence’s name.
* An identity column has no default, and the sequence is better
“linked” to the table, therefore you can not drop the default value
but leave the sequence around, and, conversely, can not drop the
sequence if the column is still defined.
Due to this, PostgreSQL’s authors recommendation is to use identity
columns instead of serial, unless there is the need for compatibility
with PostgreSQL older than 10[2], which is not our case.
According to PostgreSQL’s documentation[3], the identity column can be
‘GENERATED BY DEFAULT’ or ‘GENERATED ALWAYS’. In the latter case, it is
not possible to give a user-specified value when inserting unless
specifying ‘OVERRIDING SYSTEM VALUE’. I think this would make harder to
write pgTAP tests, and the old behaviour of serial, which is equivalent
to ‘GENERATED BY DEFAULT’, did not bring me any trouble so far.
[0]: https://sigmodrecord.org/publications/sigmodRecord/0403/E.JimAndrew-standard.pdf
[1]: https://www.2ndquadrant.com/en/blog/postgresql-10-identity-columns/
[2]: https://wiki.postgresql.org/wiki/Don't_Do_This#Don.27t_use_serial
[3]: https://www.postgresql.org/docs/15/sql-createtable.html
This page is more or less similar to home, in terms of database: it
has a carousel and a list of items; in this case, the definition of
campsite services.
As i said early, when adding the home carousel, this carousel has its
own relation and set of functions to manage slides. They are also
duplicated in Go code, but i think i will need to refactor it later to
a carousel package or something like that, because both relations have
the exact same fields and types, so it makes no sense to have twice the
same code.
I already did it with the CSS and JavaScript code, mostly because it was
easier to replace the `.surroundings div` selector with `.carousel`, and
because that way i can have a single template that loads and initializes
Slick.
There is no UI to create or edit service definitions, although there are
the SQL functions, because i have no more time now, and Oriol needs to
check that the style is correct for that page.
jordi fita mas