has_many :through => has_many

rubyonrails-talk
1

Hello All

This is my first time on ruby-forum so pardon if this is not posted correctly.

I am having a very similar issue regarding has_many through has_many. A logged user can create a work order and associated fields in models name alias and sub_tasks. I am using active_admin and an admin user can view and edit the above mentioned models, but when admin tries to create a sub_task I can get the following error:

Cannot modify association 'WorkOrder#sub_tasks' because the source reflection class 'SubTask' is associated to 'NameAlias' via :has_many.

the models:

class work_order < ActiveRecord::Base   has_many :name_aliases   has_many :sub_tasks, :through => :name_aliases end

class NameAlias < ActiveRecord::Base   belongs_to :work_order   has_many :sub_tasks end

class SubTask < ActiveRecord::Base   belongs_to :name_alias   belongs_to :work_order end

A pervious post mentioned a solution using an after_save method before declaring the association... but I didn't see sample code? since i am new to rails it would be helpful to see or example how this can be resolved. Thanks for your help!

Best, Fritz

2

This should be belongs_to :through name_alias. It must mirror the has_many sub_tasks :through in work_order

You should really have started a new thread for this as it is nothing to do with the original post.

Colin

3

Colin Law wrote in post #1040834:

class NameAlias < ActiveRecord::Base belongs_to :work_order has_many :sub_tasks end

class SubTask < ActiveRecord::Base belongs_to :name_alias belongs_to :work_order

This should be belongs_to :through name_alias. It must mirror the has_many sub_tasks :through in work_order

You should really have started a new thread for this as it is nothing to do with the original post.

Colin

Colin, Thanks for your reply and my apologies regarding proper placement of the is post.

I believe you said the SubTask model should mirror through in work_order?

class SubTask < ActiveRecord::Base   attr_accessible :name_alias_id, :work_order_id, :status, :title

  belongs_to :name_alias   belongs_to :work_order, :through => :name_alias

  accepts_nested_attributes_for :name_alias   accepts_nested_attributes_for :work_order

This produced a "Unknown key: through" error? Not sure I place the association in the correct model, I have attached a file for reference. I appreciate your help!

Attachments: http://www.ruby-forum.com/attachment/6910/has_many_through.txt

4

Sorry, I was talking drivel. belongs_to :through is not supported. You should just have belongs_to :name_alias.

Colin

5

By the way, in the attachment you have multiple default scopes for WorkOrder. I think only one is allowed. You can order by multiple fields in one scope of course if that is what you want. Be careful with specifying the order in default scope though, it is not possible to override this (or at least it did not used to be possible) as the default scope order is applied *after* any others.

Colin

6

Colin Law wrote in post #1040893:

belongs_to :work_order

of the is post. accepts_nested_attributes_for :name_alias accepts_nested_attributes_for :work_order

This produced a "Unknown key: through" error? Not sure I place the association in the correct model, I have attached a file for reference. I appreciate your help!

Attachments: http://www.ruby-forum.com/attachment/6910/has_many_through.txt

By the way, in the attachment you have multiple default scopes for WorkOrder. I think only one is allowed. You can order by multiple fields in one scope of course if that is what you want. Be careful with specifying the order in default scope though, it is not possible to override this (or at least it did not used to be possible) as the default scope order is applied *after* any others.

Colin

Thanks, make sense regarding default scope... still getting the error? wired, that a logged user can create and edit sub_task, but admin user via acitve_admin can edit but no create a sub_task?

Do you/available for consulting/help with a projects? if so, how does it work? per hour, etc..

Thanks and have a great day

Best, Fritz

7

Colin Law wrote in post #1040893:

belongs_to :work_order

of the is post. accepts_nested_attributes_for :name_alias accepts_nested_attributes_for :work_order

This produced a "Unknown key: through" error? Not sure I place the association in the correct model, I have attached a file for reference. I appreciate your help!

Attachments: http://www.ruby-forum.com/attachment/6910/has_many_through.txt

By the way, in the attachment you have multiple default scopes for WorkOrder. I think only one is allowed. You can order by multiple fields in one scope of course if that is what you want. Be careful with specifying the order in default scope though, it is not possible to override this (or at least it did not used to be possible) as the default scope order is applied *after* any others.

Colin

Thanks, make sense regarding default scope... still getting the error?

Is that a question? Did you add the id column to the table and run the migration? Show us the complete error message and stack trace and the section of your code that is causing it.

wired, that a logged user can create and edit sub_task, but admin user via acitve_admin can edit but no create a sub_task?

It is executing different code or with different data and causing the error. Nothing weird about it.

Do you/available for consulting/help with a projects? if so, how does it work? per hour, etc..

No, I just try to help out in my spare time.

Colin

8

Colin Law wrote in post #1040893:

belongs_to :work_order

of the is post. accepts_nested_attributes_for :name_alias accepts_nested_attributes_for :work_order

This produced a "Unknown key: through" error? Not sure I place the association in the correct model, I have attached a file for reference. I appreciate your help!

Attachments: http://www.ruby-forum.com/attachment/6910/has_many_through.txt

By the way, in the attachment you have multiple default scopes for WorkOrder. I think only one is allowed. You can order by multiple fields in one scope of course if that is what you want. Be careful with specifying the order in default scope though, it is not possible to override this (or at least it did not used to be possible) as the default scope order is applied *after* any others.

Colin

Thanks, make sense regarding default scope... still getting the error?

Is that a question? Did you add the id column to the table and run the migration?

What am I talking about? That was someone else in a different thread. Ignore the id comment.

Colin