how to find what all associations have dependent: destroy associated with them from a concern

[Aravind Gopalakrishnan]

I am building a soft delete solution a la https://github.com/discourse/discourse/blob/master/app/models/concerns/trashable.rb . Right now I am manually finding which all associated models need to be deleted when a model is deleted and doing it manually in each model which of course is a not a good practice. How do I do it? I don't want to use a gem, I want to write logic in my own hands.

[Taras Matsyk]

Hi Aravind,

I am not sure if I understood your question correctly but I will give a
try.
I think you want to delete all associated records with another type of
the Model.

class Body
has_many: boobs, dependent: :destroy
end

>> In this instance destroy parameter is responsible for generating/using code
that removes all dependent boob if the body instance is destroyed.


Did I get you right?

--
Posted via http://www.ruby-forum.com/.

[Matt Jones]

On Saturday, 18 July 2015 01:56:43 UTC-5, Aravind Gopalakrishnan wrote:

I am building a soft delete solution a la https://github.com/discourse/discourse/blob/master/app/models/concerns/trashable.rb . Right now I am manually finding which all associated models need to be deleted when a model is deleted and doing it manually in each model which of course is a not a good practice. How do I do it? I don't want to use a gem, I want to write logic in my own hands.

The place to start is `reflect_on_all_associations`:

http://api.rubyonrails.org/classes/ActiveRecord/Reflection/ClassMethods.html#method-i-reflect_on_all_associations 

This will give you all the associations defined for the model. You can then request the option you're interested in thus:

```

klass.reflect_on_all_associations do |reflection|

  if reflection.options[:dependent]

    # do something with it

  end

end

```

--Matt Jones