ruby on Rails: Creating models from existing database?

As you have already tables in db then no need of scaffold or generate model command, as it will generate migration file too.

simple create user.rb file under models folder.

class User < ActiveRecord::Base
end

then run

rails g controller users

this above command will create controller and views for it.

If you want to create new model and CRUD then

rails g scaffold ModelName field_name:data_type field2_name:data_type

above command will generate model, controller with CRUD methods, migration file and views

for more info http://www.tutorialspoint.com/ruby-on-rails/rails-scaffolding.htm

Note: I hope you have configure database connection via config/database.yml file to use existing database

You can use rails generators to create a scaffold, which will create model, controllers with all CRUD methods and basic views for you, implementing the CRUD actions.

For example, lets say you want to create a student model with name, age and address fields in your database, you'll generate like this

rails generate scaffold Student name:string age:integer address:string

This will generate these files for you

app/controllers/students_controller.rb  # StudentsController
app/models/student.rb  # Student model
app/views/student/ * # all view files for your student model
db/migrate/migrations_file_for_student.rb

You can always create these files manually. And write its methods yourself. Let me know if it helps.

Update

If you have an existing database, make sure you write your you have set up your database.yml file correctly, to connect your app to the right database.

Next create models, but not the migration files(hence you'll have to create user.rb inside app/models manually.)

Test if its working: Open rails console and type

User.all #will list all existing users in the console

to see if everything goes well.

Next you need to create controller and views for your. You can create scaffold_controller instead of controller which also create views for you.

rails g scaffold_controller User email first_name last_name

This will create all the views for you, and users_controller with CRUD methods, but no models or migrations files.

Hope this helps, let me know if there is anything else.

follow below step

1. rails g model model_name field_name1:field_data_type field_name:field_data_type ex. rails g user name:string email:string
2. rails g controller controller_name ex. rails g controller users // add specified method in controller and perform operations.

This is an old question but the answer provided here doesn't work for me as I wanted everything you can typically scaffold. I was trying to find out myself and here's how.

1. First create the model for the existing table - an empty class like the example below is fine:

class Person < ApplicationRecord
end

2. Generate the accompanying controller actions and views by running the following:

rails generate scaffold_controller people

The scaffold_controller command is the key, it's not a command you see appear in googled examples!