Ruby-on-rails – Rails: How to run `rails generate scaffold` when the model already exists


I'm new to Rails so my current project is in a weird state.

One of the first things I generated was a "Movie" model. I then started defining it in more detail, added a few methods, etc.

I now realize I should have generated it with rails generate scaffold to hook up things like the routing, views, controller, etc.

I tried to generate the scaffolding but I got an error saying a migration file with the same name already exists.

What's the best way for me to create scaffolding for my "Movie" now? (using rails 3)

Best Solution

TL;DR: rails g scaffold_controller <name>

Even though you already have a model, you can still generate the necessary controller and migration files by using the rails generate option. If you run rails generate -h you can see all of the options available to you.


If you'd like to generate a controller scaffold for your model, see scaffold_controller. Just for clarity, here's the description on that:

Stubs out a scaffolded controller and its views. Pass the model name, either CamelCased or under_scored, and a list of views as arguments. The controller name is retrieved as a pluralized version of the model name.

To create a controller within a module, specify the model name as a path like 'parent_module/controller_name'.

This generates a controller class in app/controllers and invokes helper, template engine and test framework generators.

To create your resource, you'd use the resource generator, and to create a migration, you can also see the migration generator (see, there's a pattern to all of this madness). These provide options to create the missing files to build a resource. Alternatively you can just run rails generate scaffold with the --skip option to skip any files which exist :)

I recommend spending some time looking at the options inside of the generators. They're something I don't feel are documented extremely well in books and such, but they're very handy.