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.
Thanks a lot for answer, Unfortunately, it is an site existing for several years, so I cant change model, so I really need to be able to change “manually” the table_name or to make like a patch forcing to check if table_name has been changed and then update association cache
