Create/Update Multiple Many-to-Many Records Through Single Form

Question

I'm trying to create a system similar to the functionality of an ecommerce system. A table is displayed with a list of products, with a text boxes for entering the desired quantity of each product. At the bottom of the table is a button to process the purchase, this should then create an Inventory record for each of the products with a quantity of more than 0, unless a record already exists for that customer, in which case it should increment it by the stated value.

I have absolutely no idea how to even begin doing this in Rails, or what to search for to find answers, any pointers in the right direction would be great. I have a lot of experience with C-style languages, but RoR is very different and I just don't know where to begin with this.

Associations:

Customer

• has_many :inventories
• has_many :products, :through => inventories

Inventory

• belongs_to :customer
• belongs_to :product

Product

• has_many :inventories
• has_many :customers, :through => :inventories

Answer 1

These are called nested forms. Ryan Bates probably has the best crash course on the topic:

http://railscasts.com/episodes/196-nested-model-form-part-1

http://railscasts.com/episodes/197-nested-model-form-part-2