Rails Cheat Sheet to create migration

2 min readApr 4, 2021

This blog will be a lifesaver for some. I am going to share with you the shortcut to create models, tables and migrations in rails using the active record migrations.

Create a new table

rails g model Restaurant name:string

This results in the following migrations

class CreateRestaurants < ActiveRecord::Migration
def change
create_table :restaurants do |t|
t.string :name
t. timestamps null: false
end
end
end

If you want to generate table with more columns you could just put the name of the column and the data type next to each other. For example

rails g model Restaurant name:string count:integer supplier:references

Will result in the following migrations

rails g model Restaurant name:string

This results in the following migrations

class CreateRestaurants < ActiveRecord::Migration
def change
create_table :restaurants do |t|
t.string :name
t.integer :count
t.references :supplier, index: true, foreign_key: true
t. timestamps null: false
end
end
end

Add a column

Lets say we want to add a column locations of type string to our restaurant model

rails g migration AddLocationsToRestaurant locations: string

The resulting migrations would be

class AddLocationsToRestaurant < ActiveRecord: Migration
def change
add_column :restaurants, :locations, :string
end
end

You can also add foreign key with this method. For example we want to add a foreign key Waiter, we can apply the same method, replacing name and type

rails g migration AddWaiterToRestaurant waiter:references

Remove a Column

To remove the locations column we just added

rails g migration RemoveLocationsFromRestaurant locations

Results in

class RemoveLocationsFromRestaurant < ActiveRecord::Migration
def change
remove_column :restaurants, :locations, :string
end
end

Rename a Column

Let’s say we want to rename our location column to rating

rails g migration RenameRestaurantLocationToRating

Manually add the rename_column to the resulting migrations

class RenameRestaurantLocationToRating < ActiveRecord::Migration
def change
rename_column :restaurants, :location, :rating
end
end

Running Migrations

rake db:migrate

In production:

rake db:migrate RAILS_ENV=”production”

I hope that this is helpful. For more migrations check out the official active record migrations link provided in the References

References

https://guides.rubyonrails.org/active_record_migrations.html