class User<<ActibeRecord::Base
json_column:data
end
class Post <<ActibeRecord::Base
json_column —info
end
By specifying the columns for each model in this way, I want to be able to add processing before saving and when referring to the values, but I don't know how to do it.
class ActiveRecord::Base
before_save —before
after_find —After
private
def before
# Cast the value specified by json_column into a string
end
after
# JSON.parse the value specified in json_column
end
end
This is an image that moves by installing something like this in raols_root/config/initializers/json_column.rb.
If this is the case, I think I can implement it if I only know how to get the value specified in json_column.
Also, what is the name of this json_column?
I'm at a loss because I don't know how to check.
I would appreciate it if you could tell me the sample source and reference site.
Thank you for your cooperation.
*This time, I used json as an example for easy understanding, but the actual action I want to take is different.
ruby-on-rails ruby
What about class_attribute
class ApplicationRecord <ActiveRecord::Base
self.abstract_class = true
class_attribute —json_column
before_save —before
private
def before
p [self.class.json_column, self [json_column]]
end
end
class User<ApplicationRecord
self.json_column=:data
end
class Post <ApplicationRecord
self.json_column= —info
end
User.create (data: 'xxx')
Post.create (info: 'yyyy')
If you want to do this by hooking the timing of validation, saving it to the database, etc.
Active Record Callback https://railsguides.jp/active_record_callbacks.html
If you want to detect a change in the model value
Active Model Dirty Module
https://railsguides.jp/active_model_basics.html#dirty%E3%83%A2%E3%82%B8%E3%83%A5%E3%83%BC%E3%83%AB
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