Forum: Ruby on Rails Associated child records not created on creation of a parent.

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82ade93bd34b4d7c756ecd1ca95eeeef?d=identicon&s=25 Master Chief (Guest)
on 2009-02-19 03:12
(Received via mailing list)
I am trying to create a record with association.  Within the create
method, I would also like to pre-populate dependent (has_many) records
from a template in the database.

The child records are <u>mysteriously rolled back </u> if I insert
them in a loop. If I try to insert a single child record, it works.I
have read the books and tried to google my way out of this but am at a
dead end.  Any help is appreciated.

Problem Statement ------------
     PrototypeModel has many Departments .

     Departments may also be grouped within Departments.

Trying to create a new PrototypeModel and populating the departments
(behind the scenes) from a template PrototypeModel specified by the
user in params[:prototype_model][:parent_id].

The save of the PrototypeModel fails as the new Department records are
invalid.
       I checked the instances and find that the department.id is
nil.  But that id is supposed to be populated by the associated
save!   If I replace the departments.build argument in the
controller::create with a set of static arguments like :name => 'Test
name', :description=> 'Test Desc'   then it works. though only one
hard code department is created :-(

Just cant get my head around this. Code is below:

Code :

   1. class PrototypeModel < ActiveRecord::Base
   2.   belongs_to :author, :class_name => 'User'
   3.   has_many :departments
   4.   belongs_to :prototype_model
   5.   acts_as_tree :foreign_key => "parent_id"
   6. end


Code :

   1. class Department < ActiveRecord::Base
   2.   validates_presence_of :name, :description
   3.   validates_presence_of :parent_id
   4.   acts_as_tree :foreign_key => "parent_id"
   5.   belongs_to :department
   6.   belongs_to :prototype_model
   7. end


Code :

   1.   # POST /prototype_models
   2.   # POST /prototype_models.xml
   3.   def create
   4.
   5.     @template_model = PrototypeModel.find( params
[:prototype_model][:parent_id] )
   6.   template_departments = @template_model.departments
   7.
   8.     @prototype_model = PrototypeModel.new(params
[:prototype_model])
   9.   @prototype_model.author = current_user
  10.
  11.   for mydepartment in template_departments
  12.     logger.debug "Cloning Department #{mydepartment.name}"
  13.
  14.     newDepartment= @prototype_model.departments.build( :name =>
mydepartment.name, :description=>
mydepartment.description, :parent_id=> mydepartment.parent_id  )
  15.   end
  16.
  17.     respond_to do |format|
  18.         if @prototype_model.save
  19.         flash[:notice] = 'PrototypeModel was successfully
created.'
  20.         format.html { redirect_to(@prototype_model) }
  21.         format.xml  { render :xml => @prototype_model, :status
=> :created, :location => @prototype_model }
  22.         else
  23.         format.html { render :action => "new" }
  24.         format.xml  { render :xml =>
@prototype_model.errors, :status => :unprocessable_entity }
  25.         end
  26.     end
  27.   end

I am using Rails 2.2.2 and Ruby 1.8.6

thanks
C64e63b70be7dfed8b0742540b8b27e5?d=identicon&s=25 Mark Reginald James (Guest)
on 2009-02-19 15:40
(Received via mailing list)
Master Chief wrote:
> I am trying to create a record with association.  Within the create
> method, I would also like to pre-populate dependent (has_many) records
> from a template in the database.

I'm not exactly clear what you're doing, but here are some
comments that may help.

>    4.   acts_as_tree :foreign_key => "parent_id"
>    5.   belongs_to :department
>    6.   belongs_to :prototype_model
>    7. end

1. Are the two belongs_to associations that reference their
    own class necessary, or can you use the parent association
    generated by acts_as_tree?

2. You should use "validates_presence_of :parent" instead.
    Using the foreign key will prevent validation when the
    parent is new.  You have to make sure that either
    (1), the foreign-key is non-NULL and points to an existing
    record, or (2), that a new parent object is assigned to the
    association.

--
Rails Wheels - Find Plugins, List & Sell Plugins -
http://railswheels.com
82ade93bd34b4d7c756ecd1ca95eeeef?d=identicon&s=25 Master Chief (Guest)
on 2009-02-19 18:07
(Received via mailing list)
Thank you for your response!

1. I didnt know acts_as_tree generated an association. Removed parent
association from both classes.
2. Changed the validates_presence_of clause.

It still gave me the same errors. :-(

New Info:
I also tried after removing the vpof clause altogether in
departments.  It removed a bunch of parent queries from the log. What
remained was just a BEGIN and ROLLBACK  but no error in the log. And
in the flash area I still got the message that the department is
invalid, so it cannot save the prototype_model.

Going to add some more logging to see if I get any more info.
Have been stuck here for 3 days, so really appreciate your help!

regards
82ade93bd34b4d7c756ecd1ca95eeeef?d=identicon&s=25 Master Chief (Guest)
on 2009-02-19 19:03
(Received via mailing list)
Resolved!
One of the data sets inserted thru SQL as a template was not passing
the Validates_presence_of clauses so it was failing to insert the
association.

Thats why my static data was working.

Also changed the validates_presence_of: parent_id  to
validates_presence_of: parent

Also removed the self reference in the belongs_to...

Thanks for the nudge in the right direction! Now I can get back on
track..... :-)

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