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camper/deploy/add_home_carousel_slide.sql

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Make home page’s carousel manageable via the database I debated with myself whether to create the home_carousel relation or rather if it would be better to have a single carousel relation for all pages. However, i thought that it would be actually harder to maintain a single relation because i would need an additional column to tell one carrousel from another, and what would that column be? An enum? A foreign key to another relation? home_carousel carries no such issues. I was starting to duplicate logic all over the packages, such as the way to encode media paths or “localization” (l10n) input fields. Therefore, i refactorized them. In the case of media path, i added a function that accepts rows of media, because always need the same columns from the row, and it was yet another repetition if i needed to pass them all the time. Plus, these kind of functions can be called as `table.function`, that make them look like columns from the table; if PostgreSQL implemented virtual generated columns, i would have used that instead. I am not sure whether that media_path function can be immutable. An immutable function is “guaranteed to return the same results given the same arguments forever”, which would be true if the inputs where the hash and the original_filename columns, instead of the whole rows, but i left it as static because i did not know whether PostgreSQL interprets the “same row but with different values” as a different input. That is, whether PostgreSQL’s concept of row is the actual tuple or the space that has a rowid, irrespective of contents; in the latter case, the function can not be immutable. Just to be in the safe side, i left it stable. The home page was starting to grow a bit too much inside the app package, new that it has its own admin handler, and moved it all to a separate package.
2023-09-14 23:05:38 +00:00
-- Deploy camper:add_home_carousel_slide to pg
-- requires: roles
-- requires: schema_camper
-- requires: home_carousel
begin;
set search_path to camper, public;
create or replace function add_home_carousel_slide(media_id integer, caption text) returns integer as
$$
insert into home_carousel (media_id, caption)
values (media_id, coalesce(caption, ''))
on conflict (media_id) do update
set caption = excluded.caption
returning media_id
;
$$
language sql
;
revoke execute on function add_home_carousel_slide(integer, text) from public;
grant execute on function add_home_carousel_slide(integer, text) to admin;
commit;