That&#39;s what I think...<br>In a ideal world, removing a class or a property should imply removing associated instances naturally...<br>Another idea...One question: are classes and properties versioned as documents? I mean, if you modify a class, is it possible to keep the previous version and keep existing objects as instantiations of the older version and then new objects will be instantiations of the newer version of the class?&nbsp; We could also propose an object to be translated into the newer version with some risks.<br>
In this case, it could be simple to modify or remove properties of a class even if it would bring some complexity also... <br>Then the last problem would be class deletion which would be more violent and would need some strong warnings because objects would be deleted definitely... in this case,&nbsp; a kind of temporary bin could be interesting...<br>
<br>Pascal<br><br><div class="gmail_quote">On Tue, Mar 18, 2008 at 10:56 AM, Sergiu Dumitriu &lt;<a href="mailto:sergiu@xwiki.com">sergiu@xwiki.com</a>&gt; wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">Pascal Voitot wrote:<br>
&gt; This might seem stupid but what are the limitations in class/object<br>
&gt; deletion?<br>
&gt;<br>
<br>
</div>We don&#39;t know what to do with the data. Adding a property is simple,<br>
existing objects will not have a property and it will be added when the<br>
object is saved. But when you delete a property, what do we do? Leave it<br>
there? Delete it from all the objects?<br>
<br>
If we keep it there, it will be &quot;shadowed&quot;, as the persistence layer<br>
will not know that it exists. More, if we add back that property with<br>
the same name and another type, we&#39;ll have errors because we&#39;ll have two<br>
instances with the same identifier in two places (this is what happened<br>
when switching number types or the multiselect metaproperty of a list<br>
property).<br>
<br>
If we remove it, then we&#39;ll completely remove a lot of data. And is a<br>
warning enough for that? Probably we need a mass rollback utility that<br>
is able to revert bulk changes.<br>
<br>
My take is that we should remove the data, but what do others think?<br>
<font color="#888888">--<br>
Sergiu Dumitriu<br>
<a href="http://purl.org/net/sergiu/" target="_blank">http://purl.org/net/sergiu/</a><br>
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