Ruby on Rails - change an existing columns type in ruby on rails - ruby on rails tutorial - rails guides - rails tutorial - ruby rails
To modify an existing column in Rails with a migration, run the below command:
class AddDetailsToUsers < ActiveRecord::Migration[5.0]
def change
add_column :users, :admin, :boolean, default: false
end
endClicking "Copy Code" button will copy the code into the clipboard - memory. Please paste(Ctrl+V) it in your destination. The code will get pasted. Happy coding from Wikitechy - ruby on rails tutorial - rails guides - ruby rails - rubyonrails - learn ruby on rails - team
- This will create a new migration file in db/migration directory (if it doesn’t exist already), which will contain the file prefixed with timestamp and migration file name which contains the below content:
def change
change_column(:table_name, :column_name, :new_type)
endClicking "Copy Code" button will copy the code into the clipboard - memory. Please paste(Ctrl+V) it in your destination. The code will get pasted. Happy coding from Wikitechy - ruby on rails tutorial - rails guides - ruby rails - rubyonrails - learn ruby on rails - team
A longer and safer method
- The above code prevents the user from ever rolling back the migration.
- We can avoid this problem by splitting the change method into separate up and down methods:
def up
change_column :my_table, :my_column, :new_type
end
def down
change_column :my_table, :my_column, :old_type
end