Forum OpenACS Q&A: Re: Question regarding XoTcl-Tutorial for OpenACS
For creating acs_types from XOTcl classes, everything needed in OpenACS is created automatically, where "everything" includes among other things the views *i and *r and the function *f (e.g. xowiki_pagei, ...).
For handling data model changes, i would recommend to check what xowiki does (look at
xowiki/tcl/xowiki-callback-procs.tcl). In many situations (just adding some columns), a call to
::xowiki::update_views is sufficient (see e.g. upgrade to 0.56 for a more complex case), maybe for your problem as well.