Rails :dependent => :destroy VS :dependent => :delete_all

ruby-on-rails ruby model associations
Sergey picture Sergey · May 9, 2010 · Viewed 97.9k times · Source

In rails guides it's described like this:

Objects will be in addition destroyed if they’re associated with :dependent => :destroy, and deleted if they’re associated with :dependent => :delete_all

Right, cool. But what's the difference between being destroyed and being deleted? I tried both and it seems to do the same thing.

Answer

shingara picture shingara · May 9, 2010

The difference is with the callback.

The :delete_all is made directly in your application and deletes by SQL :

DELETE * FROM users where compagny_id = XXXX

With the :destroy, there is an instantiation of all of your children. So, if you can't destroy it or if each has their own :dependent, its callbacks can be called.

Related questions

Removing a model in rails (reverse of "rails g model Title...")

rails g model Rating user_id:integer message:string value:integer How can I completely remove this model? Thanks

Read More
Using helpers in model: how do I include helper dependencies?

I'm writing a model that handles user input from a text area. Following the advice from http://blog.caboo.se/articles/2008/8/25/sanitize-your-users-html-input, I'm cleaning up the input in the model before saving to database, using the before_validate callback. The …

Read More
Rails: Validating min and max length of a string but allowing it to be blank

I have a field that I would like to validate. I want the field to be able to be left blank, but if a user is entering data I want it to be in a certain format. Currently I am …

Read More