camper/deploy/media.sql

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-- Deploy camper:media to pg
-- requires: roles
-- requires: schema_camper
-- requires: company
-- requires: media_content
-- requires: user_profile
begin;
set search_path to camper, public;
create table media (
Replace serial columns with ‘generated by default as identity’ 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
2023-09-26 17:35:16 +00:00
media_id integer generated by default as identity primary key,
company_id integer not null references company,
content_hash bytea not null references media_content,
original_filename text not null constraint original_filename_not_empty check(length(trim(original_filename)) > 0)
);
grant select on table media to guest;
grant select on table media to employee;
grant select, insert, delete, update on table media to admin;
alter table media enable row level security;
create policy guest_ok
on media
for select
using (true)
;
create policy insert_to_company
on media
for insert
with check (
company_id in (select company_id from user_profile)
)
;
create policy update_company
on media
for update
using (
company_id in (select company_id from user_profile)
)
;
create policy delete_from_company
on media
for delete
using (
company_id in (select company_id from user_profile)
)
;
commit;