lib/hanami/model/migrator/adapter.rb in hanami-model-1.1.0.beta1 vs lib/hanami/model/migrator/adapter.rb in hanami-model-1.1.0.beta2

@@ -82,10 +82,21 @@
           Sequel::Migrator.run(connection.raw, migrations, target: version, allow_missing_migration_files: true)
         rescue Sequel::Migrator::Error => e
           raise MigrationError.new(e.message)
         end
 
+        # @since 1.1.0
+        # @api private
+        def rollback(migrations, steps)
+          table = migrations_table_dataset
+          version = version_to_rollback(table, steps)
+
+          Sequel::Migrator.run(connection.raw, migrations, target: version, allow_missing_migration_files: true)
+        rescue Sequel::Migrator::Error => e
+          raise MigrationError.new(e.message)
+        end
+
         # Load database schema.
         # It must be implemented by subclasses.
         #
         # @since 0.4.0
         # @api private
@@ -98,20 +109,40 @@
         # Database version.
         #
         # @since 0.4.0
         # @api private
         def version
-          table = connection.table(MIGRATIONS_TABLE)
+          table = migrations_table_dataset
           return if table.nil?
 
-          if record = table.order(MIGRATIONS_TABLE_VERSION_COLUMN).last
-            record.fetch(MIGRATIONS_TABLE_VERSION_COLUMN).scan(/\A[\d]{14}/).first.to_s
-          end
+          record = table.order(MIGRATIONS_TABLE_VERSION_COLUMN).last
+          return if record.nil?
+
+          record.fetch(MIGRATIONS_TABLE_VERSION_COLUMN).scan(MIGRATIONS_FILE_NAME_PATTERN).first.to_s
         end
 
         private
 
+        # @since 1.1.0
+        # @api private
+        MIGRATIONS_FILE_NAME_PATTERN = /\A[\d]{14}/
+
+        # @since 1.1.0
+        # @api private
+        def version_to_rollback(table, steps)
+          record = table.order(Sequel.desc(MIGRATIONS_TABLE_VERSION_COLUMN)).all[steps]
+          return 0 unless record
+
+          record.fetch(MIGRATIONS_TABLE_VERSION_COLUMN).scan(MIGRATIONS_FILE_NAME_PATTERN).first.to_i
+        end
+
+        # @since 1.1.0
+        # @api private
+        def migrations_table_dataset
+          connection.table(MIGRATIONS_TABLE)
+        end
+
         # @since 0.5.0
         # @api private
         attr_reader :connection
 
         # @since 0.4.0
@@ -121,13 +152,13 @@
         end
 
         # Returns a database connection
         #
         # Given a DB connection URI we can connect to a specific database or not, we need this when creating
-        # or droping a database. Important to notice that we can't always open a _global_ DB connection,
+        # or dropping a database. Important to notice that we can't always open a _global_ DB connection,
         # because most of the times application's DB user has no rights to do so.
         #
-        # @param global [Boolean] determine whether or not a connection should specify an database.
+        # @param global [Boolean] determine whether or not a connection should specify a database.
         #
         # @since 0.5.0
         # @api private
         def new_connection(global: false)
           uri = global ? connection.global_uri : connection.uri