Attachments associate records with blobs. Usually that's a one record-many blobs relationship, but it is possible to associate many different records with the same blob. If you're doing that, you'll want to declare with has_one/many_attached :thingy, dependent: false, so that destroying any one record won't destroy the blob as well. (Then you'll need to do your own garbage collecting, though).

Methods

Instance Public methods

purge()

Synchronously purges the blob (deletes it from the configured service) and destroys the attachment.

Source: 

# File activestorage/app/models/active_storage/attachment.rb, line 20
def purge
  destroy
  blob.purge
end

purge_later()

Destroys the attachment and asynchronously purges the blob (deletes it from the configured service).

Source: 

# File activestorage/app/models/active_storage/attachment.rb, line 26
def purge_later
  destroy
  blob.purge_later
end