On Saturday, 19 September 2015 12:03:47 UTC-4, Oto Iashvili wrote:
>
> Hi,
>
> I have a product class with category and a polymorphic attributes
> details_info, that depending on category go to one or another table to get
> the detail
>
>
> Class Product
> category
> details_info
>
> end
>
> Class DetailsInfo
> ...
> end
>
> Class Pencil
>
> include DetailsInfo
> type
> color
> end
>
> Class Notebook
>
> include DetailsInfo
> size
> ...
> end
>
> and to display products i do
> prds = Products.all
> prds.each do |pr|
>
> if pr.category == 'pencil'
> DetailsInfo.table_name = 'pencil'
>
> else if pr.category == 'notebook'
>
> DetailsInfo.table_name = 'notebook'
> end
>
> end
>
> (this is just kind of algo I use)
>
> All this was working fine but with rails > 4.2 , it doesnt work anymore.
> The first time pr.details_info will be called, it seems that the table
> name is cached somewhere, and then all other products are using the same
> table_name. When I check during loop, I can see that DetailsInfo.table_name
> is always correct, but still when pr.details_info will be called , it used
> the first table_name that was used. I can also see that the method
> table_name is called every step of the loop, and it return the good
> table_name, but still, the sql request search on bad table.
>
> How can I reset that ? Ive tried a lot a thing like
> emptying association_cache, also different things
> with reflect_on_all_associations, reset_column_information, reload, ...
>
>
As mentioned on rails-core, I'd recommend looking into polymorphic
associations for this. Here's a possible example:
```
class Product < ActiveRecord::Base
# the products table has two columns relevant here:
# * details_info_id, integer
# * details_info_type, string
belongs_to :details_info, polymorphic: true
end
class Pencil < ActiveRecord::Base
has_many :products, as: :details_info
end
class Notebook < ActiveRecord::Base
has_many :products, as: :details_info
end
```
Given those models, if you retrieve a list of Product objects you should be
able to access each one's `details_info` from the correct tables.
If you're still unsure how to proceed, more detail on the specifics of your
schema and desired functionality would be useful.
--Matt Jones
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