🗂️ Create a model in Ruby on Rails
January 30, 2020
To store data in Ruby on Rails you use a model (The M in MVC). Models communicate with the database of the site.
To make a model with the attributes of name and email in the command line type
rails generate model User name:string email:string
Notice that the
User model is singular. There are two optional parameters,
email:string. This tells Rails what attributes you want and the type you want them to to be.
generate command you typed makes a mirgration file inside of the
db/migrate folder so we can change the data gradually. In this example it made a user table in the database with the columns name and email.
class CreateUsers < ActiveRecord::Migration[6.0]def changecreate_table :users do |t|t.string :namet.string :emailt.timestampsendendend
The file that created above inclues a
change method that decides the changes to the database. The change method uses a Rails method called
create_table to create a table in the database used for storing users. The
create_table method accepts a block and the block varible
|t| which means table.
Inside of the
t actually creates the name and email columns inside the database with the type of string. The last line in the block is
t.timestamps, it creates two columns in the database named
updated-at. The values for these get updated when a user is created and changed.
rails generate model User name:string email:string command also creates the model file as well in
app/models/user.rb You can see what was created
class User < ApplicationRecordend
There isn't much here yet but you don't have any users yet. It does show you
class User < ApplicationRecord which means in Ruby that the User model has all the operations as
ApplicationRecord. That topic is outside of the scope of this blog post.
I'll end it here at knowing what happens when a model in created in Rails. Thank you for reading.