1. Construct a nested params hash with data about the primary object and a belongs to and has many association.
2. Name form inputs correctly to create a nested params hash with belongs to and has many associated data.
3. Define a conventional association writer for the primary model to properly instantiate associations based on the nested params association data.
4. Define a custom association writer for the primary model to properly instantiate associations with custom logic (like unique by name) on the nested params association data.
5. Use fields_for to generate the association fields.

The first data model we're going to be working with today is a recipe with ingredients.

• Recipe
  • has many ingredients
  • title:string
• Ingredient
  • belongs to a recipe
  • ingredient.name: string
  • ingredient.quantity: string

The models and show routes and associations have been set up for you.

Build a recipe form that accepts two ingredients! It should automatically create the new Ingredient objects.

View Basic Nested Forms Lab on Learn.co and start learning to code for free.