Scaffolding in Rails while defining nullable fields and foreign keys

Question

I'm just figuring out my way around rails but I need a little help with the rails generate scaffold command.

Here's the command that I'd like to use

rails generate scaffold Expense user:??? name:string description:text

I'd like the description field to be nullable and the users field to be linked to another Model — in this case I'd like to create a foreign key to the Users. I'm using the devise authentication framework.

I've read that many RoR developers try and avoid the scaffolding method and opt for the manual approach instead but my web-app is quite simple and I've thought of going the scaffolding way.

Answer 1

Scaffolding only generates the migration that you then run. Once the file is generated simply crack open the generated migration and adjust any of the values you need specific constraints on. By default columns are set to null unless you specify otherwise e.g.:

  create_table "slugs", :force => true do |t|
    t.integer  "sequence",                     :default => 1, :null => false
    t.string   "sluggable_type", :limit => 40
    t.string   "scope",          :limit => 40
    t.datetime "created_at"
  end

This is the code generated by the friendly_id plugin as you can see they have specified that the sequence column cannot be null while the other fields have other constraints.