rails generate model

Question

I'm trying to follow instructions from the book "Head First Rails" and on page 50 it says to create a model but I am unable to create a model using the rails command.

When I type this at this prompt: localhost:~ home$

 rails generate model ad name:string description:text price:decimal seller_id:integer email:string img_url:string

I get this:

Usage:
  rails new APP_PATH [options]

Options:
  -r, [--ruby=PATH]              # Path to the Ruby binary of your choice
                                 # Default: /Users/home/.rvm/rubies/ruby-1.9.3-p125/bin/ruby
  -b, [--builder=BUILDER]        # Path to a application builder (can be a filesystem path or URL)
  -m, [--template=TEMPLATE]      # Path to an application template (can be a filesystem path or URL)
      [--skip-gemfile]           # Don't create a Gemfile
      [--skip-bundle]            # Don't run bundle install
  -G, [--skip-git]               # Skip Git ignores and keeps
  -O, [--skip-active-record]     # Skip Active Record files
  -S, [--skip-sprockets]         # Skip Sprockets files
  -d, [--database=DATABASE]      # Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite3/frontbase/ibm_db/sqlserver/jdbcmysql/jdbcsqlite3/jdbcpostgresql/jdbc)
                                 # Default: sqlite3
  -j, [--javascript=JAVASCRIPT]  # Preconfigure for selected JavaScript library
                                 # Default: jquery
  -J, [--skip-javascript]        # Skip JavaScript files
      [--dev]                    # Setup the application with Gemfile pointing to your Rails checkout
      [--edge]                   # Setup the application with Gemfile pointing to Rails repository
  -T, [--skip-test-unit]         # Skip Test::Unit files
      [--old-style-hash]         # Force using old style hash (:foo => 'bar') on Ruby >= 1.9

Runtime options:
  -f, [--force]    # Overwrite files that already exist
  -p, [--pretend]  # Run but do not make any changes
  -q, [--quiet]    # Suppress status output
  -s, [--skip]     # Skip files that already exist

Rails options:
  -h, [--help]     # Show this help message and quit
  -v, [--version]  # Show Rails version number and quit

Description:
    The 'rails new' command creates a new Rails application with a default
    directory structure and configuration at the path you specify.

    You can specify extra command-line arguments to be used every time
    'rails new' runs in the .railsrc configuration file in your home directory.

    Note that the arguments specified in the .railsrc file don't affect the
    defaults values shown above in this help message.

Example:
    rails new ~/Code/Ruby/weblog

    This generates a skeletal Rails installation in ~/Code/Ruby/weblog.
    See the README in the newly created application to get going.
localhost:~ home$

I am using Rails -v 3.2.8 and Ruby 1.9.3p125

I think that may be the problem. I have no project dir. The book is written for rails version 2.1 In this tutorial I was to create a directory using 'rails mebay' but that command does not work in Rails 3.2.8. I'm not supposed to use 'rails new mebay' because I'm supposed to manually create the models and controllers. I think there is a step missing in the book. — Livi17
– Livi17, Commented Aug 12, 2012 at 18:26
Style note: models should be capitalized, i.e. ad should be Ad. — Velizar Hristov
– Velizar Hristov, Commented Apr 6, 2022 at 16:56

Anselm · Accepted Answer · 2016-09-18 10:05:55Z

101

The code is okay but you are in the wrong directory. You must run these commands inside your rails project-directory.

The normal way to get there from scratch is:

$ rails new PROJECT_NAME
$ cd PROJECT_NAME
$ rails generate model ad \
    name:string \ 
    description:text \
    price:decimal \
    seller_id:integer \
    email:string img_url:string

edited Sep 18, 2016 at 10:05

Anselm

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answered Aug 12, 2012 at 18:28

Marcel Hebing

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5 Comments

Livi17 Over a year ago

See this lesson was intended to show you how to manually create models and controllers. It says that using "rails new mebay" creates a scaffolded app, but a scaffolded app provides more than we need. So we are supposed to manually create the model first using "rails generate model ad blah:string". Except it doesn't tell us how to create the app directory first. I think there is a step missing in the book.

Livi17 Over a year ago

I'll try your suggestion above

Marcel Hebing Over a year ago

The command rails new mebay doesn't generate a scaffold app. It only produces the skaleton of a rails-app. Without that, you cannot start to write your application.

Livi17 Over a year ago

Oh, ok. My mistake. I followed your steps and it seems to work. The book still misses a step explaining to do this first "rails new PROJECT_NAME". Thanks for your help!

Roman Malkevych Over a year ago

An abbreviated version of this command is rails g model ModelName column_name:string

I am PK · Accepted Answer · 2014-12-12 17:03:32Z

The error shows you either didn't create the rails project yet or you're not in the rails project directory.

Suppose if you're working on myapp project. You've to move to that project directory on your command line and then generate the model. Here are some steps you can refer.

Example: Assuming you didn't create the Rails app yet:

$> rails new myapp
$> cd myapp

Now generate the model from your commandline.

$> rails generate model your_model_name

JPRLCol · Accepted Answer · 2018-01-27 19:34:47Z

4

For me what happened was that I generated the app with rails new rails new chapter_2 but the RVM --default had rails 4.0.2 gem, but my chapter_2 project use a new gemset with rails 3.2.16.

So when I ran

rails generate scaffold User name:string email:string

the console showed

Usage:
   rails new APP_PATH [options]

So I fixed the RVM and the gemset with the rails 3.2.16 gem , and then generated the app again then I executed

 rails generate scaffold User name:string email:string

and it worked

edited Jan 27, 2018 at 19:34

answered Feb 10, 2014 at 16:07

JPRLCol

20012 silver badges30 bronze badges

Comments

texmex5 · Accepted Answer · 2013-02-09 10:06:53Z

2

You need to create new rails application first. Run

rails new mebay
cd mebay
bundle install
rails generate model ...

And try to find Rails 3 tutorial, there are a lot of changes since 2.1 Guides (http://guides.rubyonrails.org/getting_started.html) are good start point.

edited Feb 9, 2013 at 10:06

texmex5

4,3441 gold badge28 silver badges28 bronze badges

answered Aug 12, 2012 at 18:32

dimuch

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