Rails: example how to user change_column_null

20190626011110_add_jti_to_users.rb

# db/migrations/20190626011110_add_jti_to_users
class AddJtiToUsers < ActiveRecord::Migration[6.1]
  def change
    add_column :users, :jti, :string
    
    # populate jti so we can make it not nullable
    User.all.each do |user|
      user.update_column(:jti, SecureRandom.uuid)
    end
    
    change_column_null :users, :jti, false
    add_index :users, :jti, unique: true
  end
end