Migration to create tables using CoreData file

create_models_from_core_data.rb

# gem 'core_data'

class CreateModelsFromCoreData < ActiveRecord::Migration
  TYPE_MAP = {
               "Boolean" => 'boolean',
               "Date" => 'datetime',
               "Integer 32" => 'integer',
               "String" => 'string',
             }

  def up
    schema = CoreData::DataModel.new("#{Rails.root}/db/data.xcdatamodeld")
    entities = schema.entities
    entities.each do |entity|
      create_table entity.name.tableize.to_sym do |t|
        entity.attributes.each do |attribute|
          t.send(TYPE_MAP[attribute.type], attribute.name.underscore.to_sym)
        end

        entity.relationships.each do |relationship|
          t.send('integer', "#{relationship.name.underscore}_id".to_sym) if relationship.to_one?
        end

        t.timestamps
      end
    end
  end

  def down
    schema = CoreData::DataModel.new("#{Rails.root}/db/sekken.xcdatamodeld")
    entities = schema.entities
    entities.each do |entity|
      drop_table entity.name.tableize.to_sym
    end
  end
end