Update all existing model IDs to UUIDv7 in a Ruby on Rails application

update_ids_UUIDv7.rb

require 'uuid7'

def update_ids(model_class)
  ActiveRecord::Base.transaction do
    records = if model_class.column_names.include?('seq')
                # Sort by the 'seq' column if the model has it, as it describes the sequence of the records
                model_class.order(:seq)
              elsif model_class.column_names.include?('created_at')
                # Sort by the 'created_at' column, which is automatically generated by Ruby on Rails with 't.timestamps'
                model_class.order(:created_at)
              else
                model_class.order(:id)
              end

    records.each do |record|
      new_id = UUID7.generate
      model_class.where(id: record.id).update_all(id: new_id)
    end
  end
end

Rails.application.eager_load!

models = ApplicationRecord.descendants
puts models.inspect # Show all models

models.each do |model|
  if model.column_for_attribute(:id)&.type == :uuid
    puts "Updating IDs for #{model.name}..."
    update_ids(model)
  else
    puts "Skipping #{model.name} (id is not uuid)"
  end
end