<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">Thanks Robert.<DIV><BR class="khtml-block-placeholder"></DIV><DIV>I will write some test cases and see how it behaves. I just wanted to know before I spent the time to do it :)</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Thanks,</DIV><DIV>Waldo</DIV><DIV><BR><DIV><DIV>On Dec 30, 2005, at 10:46 AM, Robert L. Read wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"> The best way to answer this question would be to look at, or write some new, tests.<BR> <BR> I evolve classes all the time, and have never noticed a problem, at least if you add<BR> a slot that is not required at object construction time. Obviously, it is possible to add<BR> a slot in fact needed for the object to be wholesome, and elephant can't make something<BR> up in such a case.<BR> <BR> In one case I think I actually wrote a little code to:<BR> <BR> (map-btree #'(create-and-store a new object of class X) (all-objects of class Y))<BR> <BR> That will always work if you have a class evolution that you just can't get around<BR> any other way; that is the basic strategy behind inter-store migration.<BR> <BR> So I agree with Ben: it basically works, probably has glitches if you do something<BR> complicated, but there is, by writing enough (relatively simple) code, always a way out.<BR> <BR> <BR> <BR> On Thu, 2005-12-29 at 11:52 -0600, Ben wrote: <BLOCKQUOTE type="CITE"> <PRE><FONT color="#000000">it should be relatively class friendly. it should even support fancy</FONT>
<FONT color="#000000">stuff like change-class. there's talk about this in the documentation</FONT>
<FONT color="#000000">somewhere...</FONT>
<FONT color="#000000">B</FONT>
<FONT color="#000000">On 12/29/05, Waldo Rubinstein <<A href="mailto:waldo@trianet.net">waldo@trianet.net</A>> wrote:</FONT>
<FONT color="#000000">> Is Elephant friendly with class evolution? For example, if I create a</FONT>
<FONT color="#000000">> CLOS object with, say 5 fields, and store some instances in an</FONT>
<FONT color="#000000">> elephant DB and then the CLOS definition of the class changes to add</FONT>
<FONT color="#000000">> a sixth field. What will happen to the existing five objects when</FONT>
<FONT color="#000000">> retrieved? Will new objects be stored with the new field definition?</FONT>
<FONT color="#000000">></FONT>
<FONT color="#000000">> Thanks,</FONT>
<FONT color="#000000">> Waldo</FONT>
<FONT color="#000000">></FONT>
<FONT color="#000000">> _______________________________________________</FONT>
<FONT color="#000000">> elephant-devel site list</FONT>
<FONT color="#000000">> <A href="mailto:elephant-devel@common-lisp.net">elephant-devel@common-lisp.net</A></FONT>
<FONT color="#000000">> <A href="http://common-lisp.net/mailman/listinfo/elephant-devel">http://common-lisp.net/mailman/listinfo/elephant-devel</A></FONT>
<FONT color="#000000">></FONT>
<FONT color="#000000">_______________________________________________</FONT>
<FONT color="#000000">elephant-devel site list</FONT>
<FONT color="#000000"><A href="mailto:elephant-devel@common-lisp.net">elephant-devel@common-lisp.net</A></FONT>
<FONT color="#000000"><A href="http://common-lisp.net/mailman/listinfo/elephant-devel">http://common-lisp.net/mailman/listinfo/elephant-devel</A></FONT>
</PRE> </BLOCKQUOTE> </BLOCKQUOTE></DIV><BR></DIV></BODY></HTML>