music_library/backlog/docs/doc-15 - Research-Add-menu-action-to-empty-a-set.md/doc-16 - Research-Add-menu-action-to-empty-a-set.md

id, title, type, created_date

id	title	type	created_date
doc-16	Research: Add menu action to empty a set	specification	2026-05-09 17:58

Research: Add menu action to empty a set

Current state

Both the index (RecordSetLive.Index) and show (RecordSetLive.Show) views have a dropdown menu on each set with two actions:

• Edit — dropdown_link that patches to the edit form
• Delete — dropdown_button with phx-click="delete_set" and a data-confirm prompt

The RecordSets context currently provides remove_record_from_set/2 for removing individual records, and delete_record_set/1 for deleting the entire set (including its items via the has_many association's on_delete behavior). There is no function to remove all items from a set while keeping the set itself.

Approach

Since the user has confirmed this is a straightforward feature, there's a single clear implementation route:

1. Context: Add empty_record_set/1

Add a new function to MusicLibrary.RecordSets that deletes all RecordSetItem rows for a given set in a single DELETE query, then returns the reloaded (now empty) record set. This avoids N+1 deletion and keeps the set metadata intact.

2. UI: Add "Empty" action to both dropdowns

In both index.ex and show.ex, add a new dropdown_button with:

• Text: gettext("Empty")
• phx-click="empty_set"
• data-confirm for safety: gettext("Remove all records from this set?")

And add the corresponding handle_event("empty_set", ...) handler in each LiveView.

3. Tests

• Unit test for RecordSets.empty_record_set/1
• LiveView test for the "empty_set" event in the index view
• LiveView test for the "empty_set" event in the show view

Architecture impact

Touchpoint	Impact
MusicLibrary.RecordSets	New public function empty_record_set/1
MusicLibraryWeb.RecordSetLive.Index	New event handler + dropdown button
MusicLibraryWeb.RecordSetLive.Show	New event handler + dropdown button
No schema changes needed	RecordSetItem already has on_delete: :delete_all via has_many
No PubSub / routes / external API changes	This is purely local

Performance

The implementation uses a single DELETE FROM record_set_items WHERE record_set_id = ? query (bulk delete). No N+1 risk. The reload is a single get_record_set!/1 call that preloads the (now empty) items list. This is the same pattern already used by delete_record_set/1 (which relies on cascading deletes) and remove_record_from_set/2 (which deletes one item and reloads).

Documentation updates

• docs/architecture.md — no changes needed (no new modules, schemas, or subsystems)
• docs/project-conventions.md — no changes needed (follows existing patterns)