API: Subform

The Subform action is unique because it is only used by other controllers. When some other controller is displaying a Create or Update form with an association to the model configured on this controller, the other controller will try and use the subform settings from this controller to display its form.

If this configuration isn’t being used, you may need to override active_scaffold_controller_for and define your own ActiveRecord => ActionController lookup rules. See ApiCore for more information.

columns local

Lets you define the set of columns used by other controllers on their Create and Update forms. When the other controllers need to display a summary sub-form for the record scaffolded on this model, they will attempt to use this set of columns.

Example:
config.subform.columns.exclude :company_type