# File lib/dm-core/adapters/data_objects_adapter.rb, line 433
        def upgrade_model_storage(repository, model)
          table_name = model.storage_name(repository.name)

          if success = create_model_storage(repository, model)
            return model.properties(repository.name)
          end

          properties = []

          model.properties(repository.name).each do |property|
            schema_hash = property_schema_hash(repository, property)
            next if field_exists?(table_name, schema_hash[:name])
            statement = alter_table_add_column_statement(table_name, schema_hash)
            execute(statement)
            properties << property
          end

          properties
        end