# app/avo/resources/post.rb
class Avo::Resources::Post < Avo::BaseResource
  # ...

  def fields
    discover_columns only: [:title, :body, :published_at]
    discover_associations only: [:author, :comments]
  end
end
```

##### Default value

`nil`

#### Possible values

Array of symbols representing column or association names

</Option>

<Option name="`except`">

Specify which fields should be excluded from discovery.

```rb{6-7}