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@demisx
demisx / active_record_objects_autosave.md
Last active July 4, 2024 14:20
When Active Record Child Objects are Autosaved in Rails

belongs_to:

  1. Assigning an object to a belongs_to association does not automatically save the object. It does not save the associated object either.

has_one:

  1. When you assign an object to a has_one association, that object is automatically saved (in order to update its foreign key).
  2. In addition, any object being replaced is also automatically saved, because its foreign key will change too
  3. If either of these saves fails due to validation errors, then the assignment statement returns false and the assignment itself is cancelled.
  4. If the parent object (the one declaring the has_one association) is unsaved (that is, new_record? returns true) then the child objects are not saved. They will automatically when the parent object is saved.
@maxim
maxim / rails_load_path_tips.md
Last active January 9, 2025 00:59
How to use rails load paths, app, and lib directories.

In Rails 3

NOTE: This post now lives (and kept up to date) on my blog: http://hakunin.com/rails3-load-paths

If you add a dir directly under app/

Do nothing. All files in this dir are eager loaded in production and lazy loaded in development by default.

If you add a dir under app/something/

@rgreenjr
rgreenjr / postgres_queries_and_commands.sql
Last active May 14, 2025 00:29
Useful PostgreSQL Queries and Commands
-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query
FROM pg_stat_activity
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%'
ORDER BY query_start desc;
-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query
FROM pg_stat_activity
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'