Re: [Rails] Re: Why doesn't collection=objects on has_many :through trigger destroy callbacks on the join model?

[spike22]

Just reporting back, it works as expected on my end too. Thanks for the 
feedback. This solution feels more proper :)

Linking in the PR for the documentation change for others finding this 
thread in the future: https://github.com/rails/rails/pull/22644

Cheers,

Brendon

On Friday, December 18, 2015 at 10:43:07 AM UTC+13, spike22 wrote:
>
> Haha! very good :)
>
> On Friday, December 18, 2015 at 10:39:49 AM UTC+13, Eric Krause wrote:
>>
>> I just did that this morning. 
>>
>> On Thursday, December 17, 2015, spike22  
>> wrote:
>>
>>> Hi Eric, that's really interesting! I'll give it a whirl and report back 
>>> :) I might do a documentation pull request to clarify this too.
>>>
>>> Have a great day!
>>>
>>> Brendon
>>>
>>> On Friday, December 18, 2015 at 6:23:50 AM UTC+13, Eric Krause wrote:

 I responded on stackoverflow, but I'll do here as well so that it is 
 covered everywhere on the internet.

 In my case I was doing something similar to what you were doing and was 
 running into the same issue with the join table being deleted instead of 
 destroyed.

 I started looking through the code and I believe the documentation is 
 just out of date.
 [has_many_through_association](
 https://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations/has_many_through_association.rb#L131
 )

 All you need to do is add the dependent: :destroy to the has_many 
 :through relationship.

 class User
   has_many :partnerships, dependent: :destroy
   has_many :partners, through: :partnerships, dependent: :destroy
 end

 The pain I was dealing with was:
 
 user.partner_ids = [1,2,3]
 #creates the relationships
 user.partner_ids = []
 #was deleting the records from partnerships without callbacks.

 The dependent: :destroy on the partners relationship fixed that.  
 Callbacks are now being run and things are good again.

 Eric

 On Monday, December 14, 2015 at 5:43:57 PM UTC-7, spike22 wrote:
>
> I've asked this on on Stack Overflow but didn't receive much of a 
> response:
>
> The Rails 4 documentation says this regarding destroy callbacks on the 
> join model for a has_many :through relationship:
>
> collection=objects Replaces the collections content by deleting and 
> adding objects as appropriate. If the :through option is true callbacks 
> in 
> the join models are triggered except destroy callbacks, since deletion is 
> direct.
>
> Thankfully it's documented at least, but I want to know why on earth 
> this is the case? It makes more sense to trigger destroy callbacks (or 
> have 
> the option to) on a :through since these types of models can have destroy 
> callbacks and other associations.
>
> In my case I had a has_and_belongs_to_many relationship on the join 
> tables model off to another model. The records on that second join table 
> would never be deleted when the associated records on the first join 
> table 
> were deleted. I resorted to this which feels hacky, and I have to repeat 
> myself on each side of the :through relationship:
>
> class SchoolsTemplate < ActiveRecord::Base
>
>   belongs_to :school
>   belongs_to :template
>
>   has_and_belongs_to_many :groups
>
> end
>
>
> class School < ActiveRecord::Base
>
>   has_many :schools_templates, dependent: :destroy
>   has_many :templates, through: :schools_templates, before_remove: 
> :remove_groups_school_templates
>
>   private
>   def remove_groups_school_templates(template)
> schools_templates.where(template: template).first.groups.clear  end
>
> end
>
> There's a validation to 'ensure' uniqueness on the join tables records 
> between the two foreign keys, so that's why I can call first in the 
> callback.
>
 -- 
>>> You received this message because you are subscribed to a topic in the 
>>> Google Groups "Ruby on Rails: Talk" group.
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>>> .
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>>>  
>>> 
>>> .
>>> For more options, visit https://groups.google.com/d/optout.
>>>
>>
>>
>> -- 
>>
>> Eric Krause
>>
>

-- 
You received this message because you are 

[Rails] Re: Why doesn't collection=objects on has_many :through trigger destroy callbacks on the join model?

[Eric Krause]

I responded on stackoverflow, but I'll do here as well so that it is 
covered everywhere on the internet.

In my case I was doing something similar to what you were doing and was 
running into the same issue with the join table being deleted instead of 
destroyed.

I started looking through the code and I believe the documentation is just 
out of date.
[has_many_through_association](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations/has_many_through_association.rb#L131)

All you need to do is add the dependent: :destroy to the has_many :through 
relationship.

class User
  has_many :partnerships, dependent: :destroy
  has_many :partners, through: :partnerships, dependent: :destroy
end

The pain I was dealing with was:

user.partner_ids = [1,2,3]
#creates the relationships
user.partner_ids = []
#was deleting the records from partnerships without callbacks.

The dependent: :destroy on the partners relationship fixed that.  Callbacks 
are now being run and things are good again.

Eric

On Monday, December 14, 2015 at 5:43:57 PM UTC-7, spike22 wrote:
>
> I've asked this on on Stack Overflow but didn't receive much of a response:
>
> The Rails 4 documentation says this regarding destroy callbacks on the 
> join model for a has_many :through relationship:
>
> collection=objects Replaces the collections content by deleting and 
> adding objects as appropriate. If the :through option is true callbacks in 
> the join models are triggered except destroy callbacks, since deletion is 
> direct.
>
> Thankfully it's documented at least, but I want to know why on earth this 
> is the case? It makes more sense to trigger destroy callbacks (or have the 
> option to) on a :through since these types of models can have destroy 
> callbacks and other associations.
>
> In my case I had a has_and_belongs_to_many relationship on the join 
> tables model off to another model. The records on that second join table 
> would never be deleted when the associated records on the first join table 
> were deleted. I resorted to this which feels hacky, and I have to repeat 
> myself on each side of the :through relationship:
>
> class SchoolsTemplate < ActiveRecord::Base
>
>   belongs_to :school
>   belongs_to :template
>
>   has_and_belongs_to_many :groups
>
> end
>
>
> class School < ActiveRecord::Base
>
>   has_many :schools_templates, dependent: :destroy
>   has_many :templates, through: :schools_templates, before_remove: 
> :remove_groups_school_templates
>
>   private
>   def remove_groups_school_templates(template)
> schools_templates.where(template: template).first.groups.clear  end
>
> end
>
> There's a validation to 'ensure' uniqueness on the join tables records 
> between the two foreign keys, so that's why I can call first in the 
> callback.
>

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Re: [Rails] Re: Why doesn't collection=objects on has_many :through trigger destroy callbacks on the join model?

[Eric Krause]

I just did that this morning.

On Thursday, December 17, 2015, spike22  wrote:

> Hi Eric, that's really interesting! I'll give it a whirl and report back
> :) I might do a documentation pull request to clarify this too.
>
> Have a great day!
>
> Brendon
>
> On Friday, December 18, 2015 at 6:23:50 AM UTC+13, Eric Krause wrote:
>>
>> I responded on stackoverflow, but I'll do here as well so that it is
>> covered everywhere on the internet.
>>
>> In my case I was doing something similar to what you were doing and was
>> running into the same issue with the join table being deleted instead of
>> destroyed.
>>
>> I started looking through the code and I believe the documentation is
>> just out of date.
>> [has_many_through_association](
>> https://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations/has_many_through_association.rb#L131
>> )
>>
>> All you need to do is add the dependent: :destroy to the has_many
>> :through relationship.
>>
>> class User
>>   has_many :partnerships, dependent: :destroy
>>   has_many :partners, through: :partnerships, dependent: :destroy
>> end
>>
>> The pain I was dealing with was:
>>
>> user.partner_ids = [1,2,3]
>> #creates the relationships
>> user.partner_ids = []
>> #was deleting the records from partnerships without callbacks.
>>
>> The dependent: :destroy on the partners relationship fixed that.
>> Callbacks are now being run and things are good again.
>>
>> Eric
>>
>> On Monday, December 14, 2015 at 5:43:57 PM UTC-7, spike22 wrote:
>>>
>>> I've asked this on on Stack Overflow but didn't receive much of a
>>> response:
>>>
>>> The Rails 4 documentation says this regarding destroy callbacks on the
>>> join model for a has_many :through relationship:
>>>
>>> collection=objects Replaces the collections content by deleting and
>>> adding objects as appropriate. If the :through option is true callbacks in
>>> the join models are triggered except destroy callbacks, since deletion is
>>> direct.
>>>
>>> Thankfully it's documented at least, but I want to know why on earth
>>> this is the case? It makes more sense to trigger destroy callbacks (or have
>>> the option to) on a :through since these types of models can have destroy
>>> callbacks and other associations.
>>>
>>> In my case I had a has_and_belongs_to_many relationship on the join
>>> tables model off to another model. The records on that second join table
>>> would never be deleted when the associated records on the first join table
>>> were deleted. I resorted to this which feels hacky, and I have to repeat
>>> myself on each side of the :through relationship:
>>>
>>> class SchoolsTemplate < ActiveRecord::Base
>>>
>>>   belongs_to :school
>>>   belongs_to :template
>>>
>>>   has_and_belongs_to_many :groups
>>>
>>> end
>>>
>>>
>>> class School < ActiveRecord::Base
>>>
>>>   has_many :schools_templates, dependent: :destroy
>>>   has_many :templates, through: :schools_templates, before_remove: 
>>> :remove_groups_school_templates
>>>
>>>   private
>>>   def remove_groups_school_templates(template)
>>> schools_templates.where(template: template).first.groups.clear  end
>>>
>>> end
>>>
>>> There's a validation to 'ensure' uniqueness on the join tables records
>>> between the two foreign keys, so that's why I can call first in the
>>> callback.
>>>
>> --
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>


-- 

Eric Krause

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[Rails] Re: Why doesn't collection=objects on has_many :through trigger destroy callbacks on the join model?

[spike22]

Hi Eric, that's really interesting! I'll give it a whirl and report back :) 
I might do a documentation pull request to clarify this too.

Have a great day!

Brendon

On Friday, December 18, 2015 at 6:23:50 AM UTC+13, Eric Krause wrote:
>
> I responded on stackoverflow, but I'll do here as well so that it is 
> covered everywhere on the internet.
>
> In my case I was doing something similar to what you were doing and was 
> running into the same issue with the join table being deleted instead of 
> destroyed.
>
> I started looking through the code and I believe the documentation is just 
> out of date.
> [has_many_through_association](
> https://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations/has_many_through_association.rb#L131
> )
>
> All you need to do is add the dependent: :destroy to the has_many :through 
> relationship.
>
> class User
>   has_many :partnerships, dependent: :destroy
>   has_many :partners, through: :partnerships, dependent: :destroy
> end
>
> The pain I was dealing with was:
> 
> user.partner_ids = [1,2,3]
> #creates the relationships
> user.partner_ids = []
> #was deleting the records from partnerships without callbacks.
>
> The dependent: :destroy on the partners relationship fixed that. 
>  Callbacks are now being run and things are good again.
>
> Eric
>
> On Monday, December 14, 2015 at 5:43:57 PM UTC-7, spike22 wrote:
>>
>> I've asked this on on Stack Overflow but didn't receive much of a 
>> response:
>>
>> The Rails 4 documentation says this regarding destroy callbacks on the 
>> join model for a has_many :through relationship:
>>
>> collection=objects Replaces the collections content by deleting and 
>> adding objects as appropriate. If the :through option is true callbacks in 
>> the join models are triggered except destroy callbacks, since deletion is 
>> direct.
>>
>> Thankfully it's documented at least, but I want to know why on earth this 
>> is the case? It makes more sense to trigger destroy callbacks (or have the 
>> option to) on a :through since these types of models can have destroy 
>> callbacks and other associations.
>>
>> In my case I had a has_and_belongs_to_many relationship on the join 
>> tables model off to another model. The records on that second join table 
>> would never be deleted when the associated records on the first join table 
>> were deleted. I resorted to this which feels hacky, and I have to repeat 
>> myself on each side of the :through relationship:
>>
>> class SchoolsTemplate < ActiveRecord::Base
>>
>>   belongs_to :school
>>   belongs_to :template
>>
>>   has_and_belongs_to_many :groups
>>
>> end
>>
>>
>> class School < ActiveRecord::Base
>>
>>   has_many :schools_templates, dependent: :destroy
>>   has_many :templates, through: :schools_templates, before_remove: 
>> :remove_groups_school_templates
>>
>>   private
>>   def remove_groups_school_templates(template)
>> schools_templates.where(template: template).first.groups.clear  end
>>
>> end
>>
>> There's a validation to 'ensure' uniqueness on the join tables records 
>> between the two foreign keys, so that's why I can call first in the 
>> callback.
>>
>

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Re: [Rails] Re: Why doesn't collection=objects on has_many :through trigger destroy callbacks on the join model?

[spike22]

Haha! very good :)

On Friday, December 18, 2015 at 10:39:49 AM UTC+13, Eric Krause wrote:
>
> I just did that this morning. 
>
> On Thursday, December 17, 2015, spike22  > wrote:
>
>> Hi Eric, that's really interesting! I'll give it a whirl and report back 
>> :) I might do a documentation pull request to clarify this too.
>>
>> Have a great day!
>>
>> Brendon
>>
>> On Friday, December 18, 2015 at 6:23:50 AM UTC+13, Eric Krause wrote:
>>>
>>> I responded on stackoverflow, but I'll do here as well so that it is 
>>> covered everywhere on the internet.
>>>
>>> In my case I was doing something similar to what you were doing and was 
>>> running into the same issue with the join table being deleted instead of 
>>> destroyed.
>>>
>>> I started looking through the code and I believe the documentation is 
>>> just out of date.
>>> [has_many_through_association](
>>> https://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations/has_many_through_association.rb#L131
>>> )
>>>
>>> All you need to do is add the dependent: :destroy to the has_many 
>>> :through relationship.
>>>
>>> class User
>>>   has_many :partnerships, dependent: :destroy
>>>   has_many :partners, through: :partnerships, dependent: :destroy
>>> end
>>>
>>> The pain I was dealing with was:
>>> 
>>> user.partner_ids = [1,2,3]
>>> #creates the relationships
>>> user.partner_ids = []
>>> #was deleting the records from partnerships without callbacks.
>>>
>>> The dependent: :destroy on the partners relationship fixed that.  
>>> Callbacks are now being run and things are good again.
>>>
>>> Eric
>>>
>>> On Monday, December 14, 2015 at 5:43:57 PM UTC-7, spike22 wrote:

 I've asked this on on Stack Overflow but didn't receive much of a 
 response:

 The Rails 4 documentation says this regarding destroy callbacks on the 
 join model for a has_many :through relationship:

 collection=objects Replaces the collections content by deleting and 
 adding objects as appropriate. If the :through option is true callbacks in 
 the join models are triggered except destroy callbacks, since deletion is 
 direct.

 Thankfully it's documented at least, but I want to know why on earth 
 this is the case? It makes more sense to trigger destroy callbacks (or 
 have 
 the option to) on a :through since these types of models can have destroy 
 callbacks and other associations.

 In my case I had a has_and_belongs_to_many relationship on the join 
 tables model off to another model. The records on that second join table 
 would never be deleted when the associated records on the first join table 
 were deleted. I resorted to this which feels hacky, and I have to repeat 
 myself on each side of the :through relationship:

 class SchoolsTemplate < ActiveRecord::Base

   belongs_to :school
   belongs_to :template

   has_and_belongs_to_many :groups

 end


 class School < ActiveRecord::Base

   has_many :schools_templates, dependent: :destroy
   has_many :templates, through: :schools_templates, before_remove: 
 :remove_groups_school_templates

   private
   def remove_groups_school_templates(template)
 schools_templates.where(template: template).first.groups.clear  end

 end

 There's a validation to 'ensure' uniqueness on the join tables records 
 between the two foreign keys, so that's why I can call first in the 
 callback.

>>> -- 
>> You received this message because you are subscribed to a topic in the 
>> Google Groups "Ruby on Rails: Talk" group.
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>> https://groups.google.com/d/msgid/rubyonrails-talk/9eb239ab-b444-4b74-837d-503b589516a2%40googlegroups.com
>>  
>> 
>> .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
> -- 
>
> Eric Krause
>

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