[REBOL] Re: dbms3.r 01
From: greggirwin:mindspring at: 21-Jan-2002 10:04
Hi Charles,
<< Okay, here's another comment from someone who hasn't really worked with
this material. I believe someone else's solution was to, essentially,
create a new object. What about that? Sort of like children/evolution - if
something like that needs to be changed, couldn't you instead create a new
copy of ObjA with the additional info, then erase ObjA and replace it with
ObjA.1? >>
Sure you can. Object versioning and schema evolution are two features that
some object databases tout as major benefits. The trick is how to do it
correctly. :) Some example questions might be: If you have an object in
memory, and other code holds references to that object, what happens to
those references when you destroy, and recreate, the object? Do you re-use
the same object ID, or do you assign a new object ID so that the old version
of the object can still be accessed (or do you assign a "versioned" ID to
the old one)? Do you make a distinction between a schema change and a data
change?
Things like that. The Devil is in the details as they say.
--Gregg
