1 files changed, 11 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/schema_migration.rb b/activerecord/lib/active_record/schema_migration.rb
index a9d164e366..b5038104ac 100644
--- a/activerecord/lib/active_record/schema_migration.rb
+++ b/activerecord/lib/active_record/schema_migration.rb
@@ -5,6 +5,9 @@ require 'active_record/base'
 module ActiveRecord
   class SchemaMigration < ActiveRecord::Base
     class << self
+      def primary_key
+        nil
+      end
 
       def table_name
         "#{table_name_prefix}#{ActiveRecord::Base.schema_migrations_table_name}#{table_name_suffix}"
@@ -36,6 +39,14 @@ module ActiveRecord
           connection.drop_table(table_name)
         end
       end
+
+      def normalize_migration_number(number)
+        "%.3d" % number.to_i
+      end
+
+      def normalized_versions
+        pluck(:version).map { |v| normalize_migration_number v }
+      end
     end
 
     def version