Question regarding dependent behavior

[joep]

New to mongodb and mongoid and I basically copied an example from the docs (https://www.mongodb.com/docs/mongoid/current/reference/associations/#dependent-behavior). Code shown below.

However, when I delete a Band record the associated Album records do no seem to be deleted (which I verify in mongosh after executing the program) and instead appear to be orphaned.

Can someone please explain what I am not understanding? Thanks much!

require 'mongoid'

ENV["MONGOID_ENV"] = 'dbtesting'
Mongoid.load!(File.join(File.dirname(__FILE__), 'mongoid.yml'))

class Band
    include Mongoid::Document
    has_many :albums, dependent: :delete_all
end

class Album
    include Mongoid::Document
    belongs_to :band
end

Band.collection.drop()
Album.collection.drop()
p Band.count
# result => 0
p Album.count
# result => 0
r = Band.create()
r.albums.create()
r.albums.create()
r.albums.create()
r.albums.create()
Band.first.delete # Will delete all associated albums.
p Band.count
# result => 0
p Album.count
# result => 4 ??????

[joep]

Sorry, I just realized this should be in the 'Q&A' category.

[comandeo]

Hi @joep,

The delete method only deletes the document itself. No callbacks are triggered, no associations are deleted. Contrary, the destroy method does what is expected. If you call Band.first.destroy, the albums will be deleted.

Thank you for pointing this out, I understand that the naming of the option and the documentation of the delete method can be improved.

[joep]

Hi @comandeo,

Thanks for the quick clarification. While the nomenclature is a bit confusing, I think I might have dug deeper and resolved it on my own if not for the single line and comment in the documentation example:

Band.first.delete # Will delete all associated albums.

That comment just kept me focused on something I must be doing wrong.

[comandeo]

Oh, I did not notice that this line was also copied from the docs! This must be fixed, we raised a ticket for that - https://jira.mongodb.org/browse/MONGOID-5616

Thank you again for pointing this out!