Data Access

Every field you define on a flex column can be accessed in (potentially) several ways. As an example:

class User < ActiveRecord::Base
  flex_column :user_attributes do
    field :foo
    field :bar
  end
end

my_user = User.find(...)

From always-defined to not-always-defined:

1. Hash indexing from inside the flex-column object: always works. Custom methods you define on the flex-column object can always access fields by saying self[:foo], self[:foo] = 123, and so on. Hash-indexing is done as a HashWithIndifferentAccess, so you can use a String or a Symbol, or mix the two. Note that any attributes you haven't declared fields for won't be accessible, even this way; see unknown JSON keys for more details.
2. Hash indexing from outside the flex-column object: always works. my_user.user_attributes[:foo] = 123, x = my_user.user_attributes['foo'], and so on.
3. Flex-column methods from inside the flex-column object: always works, unless you override them. Custom methods you define on the flex-column object can access fields by simply calling a method of the same name: self.foo = 123, self.foo, and so on.
4. Flex-columns methods from outside the flex-column object: works unless you make them private. For example, my_user.user_attributes.foo = 123
5. Model methods from inside the model object: works unless (a) you turn off delegation, (b) your model has a column of the same name as the field in question, or (c) another flex column, declared afterwards (it's "last declaration wins"), has a field of the same name. For example, my_user.foo = 123, my_user.foo, and so on.
6. Model methods from outside the model object: works unless (a) you turn off delegation, (b) your model has a column of the same name as the field in question, (c) another flex column, declared afterwards (it's "last declaration wins"), has a field of the same name, or (d) you make the methods private.