Similarities between OpenACS Meta Model and XOTcl Concepts

• acs_object_types: defines specialization - similar to XOTcl classes
  
• acs_objects: defines common attributes - similar to ::xotcl::Object
• acs_attributes: defines properties of attributes - similar to attribute slots

DB-Layer is much less flexible then XOTcl:
less support for dynamic operations (adding attributes), no support for re-classing, mixins, ...