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| author | Marcel M. Cary <marcel@oak.homeunix.org> | 2018-11-13 15:29:43 -0800 |
|---|---|---|
| committer | Marcel M. Cary <marcel@oak.homeunix.org> | 2018-11-13 16:06:00 -0800 |
| commit | 39806b6d98c1dbcbaac6748274e2cc3fbfba3495 (patch) | |
| tree | 38c92dff90c53b009003aba16aefd82ec2c38b6b /guides | |
| parent | 3dea7f0615144e891d4122697638db735fbea71d (diff) | |
| download | rails-39806b6d98c1dbcbaac6748274e2cc3fbfba3495.tar.gz rails-39806b6d98c1dbcbaac6748274e2cc3fbfba3495.tar.bz2 rails-39806b6d98c1dbcbaac6748274e2cc3fbfba3495.zip | |
Describe how has_many's :dependent option affects #delete
I was puzzled about why `collection=` was destroying the removed
records on an association with `dependent: :destroy`, even after
consulting the documentation for that option. I had to dive into the
Active Record source to understand what was going on: eventually
`collection=` calls `collection.delete` on the ousted records, and it
also uses the `:dependent` option to decide how to remove records.
It would have helped me to have mention of this in the documentation for
`:dependent`, not just under `collection.delete` (which I found much
later).
Briefly mention the broader impacts of `:dependent` in the Association
Basics guide.
[ci skip]
Diffstat (limited to 'guides')
| -rw-r--r-- | guides/source/association_basics.md | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md index f75517c5ab..822dee08f0 100644 --- a/guides/source/association_basics.md +++ b/guides/source/association_basics.md @@ -1662,6 +1662,8 @@ Controls what happens to the associated objects when their owner is destroyed: * `:restrict_with_exception` causes an `ActiveRecord::DeleteRestrictionError` exception to be raised if there are any associated records * `:restrict_with_error` causes an error to be added to the owner if there are any associated objects +The `:destroy` and `:delete_all` options also affect the samantics of the `collection.delete` and `collection=` methods by causing them to destroy associated objects when they are removed from the collection. + ##### `:foreign_key` By convention, Rails assumes that the column used to hold the foreign key on the other model is the name of this model with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly: |