nested_models.md

Nested Models

In some cases, you might need to have a stored model as an attribute of another one:

class Supplier
  include StoreModel::Model

  attribute :title, :string
end

class Configuration
  include StoreModel::Model

  attribute :supplier, Supplier.to_type
end

To make it work with nested Rails forms (i.e., define a method called #{attribute_name}_attributes=) you should add accepts_nested_attributes_for :supplier, which works in the same way as the built-in Rails method, to the parent model.

Validation

If you want to validate the nested model, you must use the StoreModelValidator validator:

attribute :supplier, Supplier.to_type # existing attribute definition
validates :supplier, store_model: true

Work-around for loading database schema in Rails 7.2+

In Rails 7.2+, a private attribute registration callback has been removed and at time of writing, no replacement is available.

Due to this, when using store_model with accepts_nested_attributes_for the database schema is required to be available in your database before booting your application. This will occur for example when setting up a new environment or in CI.

The only known workaround for this currently is to load the database structure before you run your application, i.e. using psql. Please note that even rails dbconsole is affected by this and hence you have to prepare your database without touching any of your rails application whatsoever. You must also use the sql structure dump, as loading schema.rb requires to boot your application, which you won't be able to.

psql <auth flags and database name> < db/structure.sql
bundle exec rails console

See also this issue for further discussion. Please also consider contributing the necessary API to Rails so there can be a less clunky solution to this.