Forum: Ruby on Rails case study

hi,

i' trying to re-create my project from php to rails. But now Im faced 
with
a pb to witch I had solution with php, but I cant figure how to make it
work with rails

here my tables

ads
  id
  category_id
  title
  text

ad_real_estate_details
  id
  ad_id
  nb_room
  floor

ad_car_details
  id
  ad_id
  color
  brand

here what I succeed to do


class Ad < ActiveRecord::Base
  attr_accessible :category_id :title, :text, :ad_real_estate_details
  has_one :ad_real_estate_details
  accepts_nested_attributes_for :ad_real_estate_details, allow_destroy: 
true
end

class AdRealEstateDetail < ActiveRecord::Base
  belongs_to :ad
  validates :ad_id, presence: true
end

but this only work for other category than real_estate

so I was thinking of polymorphism, but polymorphism mean I should add a
reference in my "ad" table to the detail tables, and remove annonce_id 
from
detail tables , what I thing is non-sense as some ads can have no 
details,
but details are non-sense without an ad.

I was also thinking of a class AdDetails, and  AdRealEstateDetail would
inherite from it, but this is not possible with rails as all subclasses
will share the same table

does anyone have a solution for this kind of problem ?

thanks

On Mon, Jan 28, 2013 at 6:27 AM, oto iashvili
<optimum.dulopin@laposte.net>wrote:

>   category_id
>   id
>   accepts_nested_attributes_for :ad_real_estate_details, allow_destroy:
> so I was thinking of polymorphism, but polymorphism mean I should add a
> reference in my "ad" table to the detail tables, and remove annonce_id from
> detail tables , what I thing is non-sense as some ads can have no details,
> but details are non-sense without an ad.
>

i think you have it right when you mentioned using polymorphic
associations.  it is fine to leave the polymorphic association
nil if the ad has no details if that's what you're worried about.


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--

On Sun, Jan 27, 2013 at 11:27 PM, oto iashvili
<optimum.dulopin@laposte.net>wrote:

>   category_id
>   id
>   ad_id
>   color
>   brand
>
> here what I succeed to do
>
>
> class Ad < ActiveRecord::Base
>   attr_accessible :category_id :title, :text, :ad_real_estate_details
>
This should be :add_real_estate_details_attributes

> but this only work for other category than real_estate
> does anyone have a solution for this kind of problem ?
> https://groups.google.com/d/msg/rubyonrails-talk/-....
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>



--
Nicolas Desprs

Hi,

thanks for answer. My pb with polymorphic is that I would have to create
first in db a ligne for ad_real_estate_details and then create my ad, 
what
is non sense for me, in terms of logic.
and it might brings some pb as I read
there 
http://stackoverflow.com/questions/3969025/accepts...

lets have another example which is almost the same

image we have Student (age, classe, ...)  and Teacher (subject_taught)
classes that inherit from User classes. I would be non sense to create
first a Teacher entity, and then to link it to User, no ?


Le lundi 28 janvier 2013 01:10:30 UTC+1, jim a crit :

On Tue, Jan 29, 2013 at 7:41 PM, oto iashvili
<optimum.dulopin@laposte.net>wrote:

> image we have Student (age, classe, ...)  and Teacher (subject_taught)
> classes that inherit from User classes. I would be non sense to create
> first a Teacher entity, and then to link it to User, no ?
>

Why are you thinking of creating the details first?  Why not create the 
ad
first, then add the details later? Sometimes, 
accepts_nested_attributes_for
is not always the answer for creating association records.  Try to look
into virtual attributes
and callbacks.


>>>
>>>   text
>>>   color
>>> end
>>> detail tables , what I thing is non-sense as some ads can have no details,
>>> inherite from it, but this is not possible with rails as all subclasses
>>> To unsubscribe from this group, send email to rubyonrails-ta...@**
>>
> email to rubyonrails-talk+unsubscribe@googlegroups.com.
>
> To post to this group, send email to rubyonrails-talk@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msg/rubyonrails-talk/-....
>
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>



--

I want to do
@ad = Ad.attributes(params[:ad])
maybe Im wrong, but as I understood about polymorphic in rails, this 
would
thow an error say that  ad_real_estate_details does not exist

as they explained here
http://stackoverflow.com/questions/3969025/accepts...


Le mardi 29 janvier 2013 13:39:18 UTC+1, jim a crit :

On Wed, Jan 30, 2013 at 6:48 PM, oto iashvili
<optimum.dulopin@laposte.net>wrote:

> I want to do
> @ad = Ad.attributes(params[:ad])
> maybe Im wrong, but as I understood about polymorphic in rails, this would
> thow an error say that  ad_real_estate_details does not exist
>
> as they explained here http://stackoverflow.**
> com/questions/3969025/accepts-**nested-attributes-for-with-**
> 
belongs-to-polymorphic<http://stackoverflow.com/questions/3969025/accepts...
>

As I've said, don't use accepts_nested_attributes_for.  Create a getter 
and
setter method for each kind of details that you want.
If you don't want to do that, create an attr_accessor for the details, 
and
create the detail record in a callback.



>>>
>>> classes that inherit from User classes. I would be non sense to create
>>>
>>>>> i' trying to re-create my project from php to rails. But now Im faced
>>>>>
>>>>>   brand
>>>>>
>>>>> details, but details are non-sense without an ad.
>>>>> subclasses will share the same table
>>>>> googlegroups**.com.
>>>>
>>>
>>
> email to rubyonrails-talk+unsubscribe@googlegroups.com.
> To post to this group, send email to rubyonrails-talk@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msg/rubyonrails-talk/-....
>
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>



--

hi

thanks for answer sorry I quite new in RoR. If I do how u said, will I 
have
to validate "manually" all the attributes for details ?

Le mercredi 30 janvier 2013 15:27:43 UTC+1, jim a crit :

On Thu, Jan 31, 2013 at 7:08 AM, oto iashvili
<optimum.dulopin@laposte.net>wrote:

> hi
>
> thanks for answer sorry I quite new in RoR. If I do how u said, will I
> have to validate "manually" all the attributes for details ?
>

Now that you've asked that, I'm not sure.  You can try to use
validates_associated and use a before_validation callback


>>>
>>
>>>>> Hi,
>>>>> image we have Student (age, classe, ...)  and Teacher (subject_taught)
>>>>
>>>>>>> hi,
>>>>>>>   title
>>>>>>>   ad_id
>>>>>>> allow_destroy: true
>>>>>>> add a reference in my "ad" table to the detail tables, and remove
>>>>>>> I was also thinking of a class AdDetails, and  AdRealEstateDetail
>>>>>>> To post to this group, send email to rubyonra...@googlegroups.**com.
>>>>>>>
>>>>> You received this message because you are subscribed to the Google
>>>>> .
>>>  --
>>> .
>  --
>
>



--

On 30 January 2013 23:08, oto iashvili <optimum.dulopin@laposte.net> 
wrote:
> hi
>
> thanks for answer sorry I quite new in RoR. If I do how u said, will I have
> to validate "manually" all the attributes for details ?

If you are new to rails there are probably many other basic features
that you are not aware of.  I suggest you work right through a good
rails tutorial such as railstutorial.org, which is free to use online.
 That will introduce you to the basics.  Also look through the Rails
Guides, the one called Active Record Validations and Callbacks should
cover what you are looking for.  Also look through the others.

Colin