Ruby on Rails ActiveRecord Creating a Model manually


While using scaffolding is a fast and easy if you are new to Rails or you are creating a new application, later it can be useful just to do it on your own ato avoid the need to go through the scaffold-generated code to slim it down (remove unused parts, etc.).

Creating a model can be as simple as creating a file under app/models.

The most simple model, in ActiveRecord, is a class that extends ActiveRecord::Base.

class User < ActiveRecord::Base

Model files are stored in app/models/, and the file name corresponds to the singular name of the class:

# user

# SomeModel

The class will inherit all the ActiveRecord features: query methods, validations, callbacks, etc.

# Searches the User with ID 1

Note: Make sure that the table for the corresponding model exists. If not, you can create the table by creating a Migration

You can generate a model and it's migration by terminal from the following command

rails g model column_name1:data_type1, column_name2:data_type2, ...

and can also assign foreign key(relationship) to the model by following command

rails g model column_name:data_type, model_name:references