Are there database backed i18n packages?

I am looking for a database backed i18n package, something similar to i18n-active_record for Rails.

Requirements

1. 
   

   Support RDBMS such as MySQL and PostgreSQL

   
   


2. 
   

   Cache the translations

   
   

Alternative Solution

If there are no such existing module, can I have a simple instruction for building one by myself?

It could be in other languages such as Java, PHP or Ruby.