How do you discover model attributes in Rails?

158
votes

I am finding it difficult to easily see what attributes/properties exist on all of my model classes since they are not explicitly defined in my class files.

To discover model attributes, I keep the schema.rb file open and flip between it and whatever code I'm writing as needed. This works but is clunky because I have to switch between reading the schema file to pick up attributes, the model class file to check methods, and whatever new code that I'm writing to call attributes & methods.

My question is, how do you discover model attributes when you're analyzing a Rails codebase for the first time? Do you keep the schema.rb file open all the time, or is there a better way that doesn't involve jumping between schema file & model file constantly?

5
ruby-on-railsactiverecord
Thanks for the answers below. It sounds like there's not a good way to declare attribute names in the model source file, but rather keep a terminal open and poke the objects to find out their properties. – gbc

5 Answers

293
votes

For Schema related stuff

Model.column_names         
Model.columns_hash         
Model.columns

For instance variables/attributes in an AR object

object.attribute_names                    
object.attribute_present?          
object.attributes

For instance methods without inheritance from super class

Model.instance_methods(false)
29
votes

There is a rails plugin called Annotate models, that will generate your model attributes on the top of your model files here is the link:

https://github.com/ctran/annotate_models

to keep the annotation in sync, you can write a task to re-generate annotate models after each deploy.

18
votes

If you're just interested in the properties and data types from the database, you can use Model.inspect.

irb(main):001:0> User.inspect
=> "User(id: integer, email: string, encrypted_password: string,
 reset_password_token: string, reset_password_sent_at: datetime,
 remember_created_at: datetime, sign_in_count: integer,
 current_sign_in_at: datetime, last_sign_in_at: datetime,
 current_sign_in_ip: string, last_sign_in_ip: string, created_at: datetime,
 updated_at: datetime)"

Alternatively, having run rake db:create and rake db:migrate for your development environment, the file db/schema.rb will contain the authoritative source for your database structure:

ActiveRecord::Schema.define(version: 20130712162401) do
  create_table "users", force: true do |t|
    t.string   "email",                  default: "", null: false
    t.string   "encrypted_password",     default: "", null: false
    t.string   "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.integer  "sign_in_count",          default: 0
    t.datetime "current_sign_in_at"
    t.datetime "last_sign_in_at"
    t.string   "current_sign_in_ip"
    t.string   "last_sign_in_ip"
    t.datetime "created_at"
    t.datetime "updated_at"
  end
end
13
votes

To describe model I use following snippet

Model.columns.collect { |c| "#{c.name} (#{c.type})" }

Again this is if you are looking pretty print to describe you ActiveRecord without you going trough migrations or hopping that developer before you was nice enough to comment in attributes.

6
votes
some_instance.attributes

Source: blog