module RuboCop::Cop::ActiveRecordHelper

def external_dependency_checksum
  return @external_dependency_checksum if defined?(@external_dependency_checksum)
  schema_path = RuboCop::Rails::SchemaLoader.db_schema_path
  return nil if schema_path.nil?
  schema_code = File.read(schema_path)
  @external_dependency_checksum ||= Digest::SHA1.hexdigest(schema_code)
end