In addition to that, you might also want to have a look at ACS Object Management. I have had a look at ams and acs-object-management some months ago. What I remember is, that I wondered why acs-object-management never made it into the core, as its approach seemed to be relatively "OpenACS-native".
Note as well, that XOTcl Core provides automatically created procs for db functions, e.g. ::xo::db::sql::acs_attribute proc create_attribute...
