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[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