Re: Proving an Upgrade is Possible

"Kenneth Downs" <knode.wants.this_at_see.sigblock> wrote in message news:0fcbn2-375.ln1_at_pluto.downsfam.net...
> mountain man wrote:

>> Only a test-conversion will tell you that. This is
>> not to say that "proving the schema upgrade is
>> possible" ---- at the schema level alone ---- is
>> not a worthwhile step in the upgrade path, as
>> in the end you need to know about any failure,
>> hopefully in advance.
>
> Not true. In the example above, I showed how you could know before the
> conversion that it would fail, without going through the conversion.
>
> I am seeking the structure of meta data that would offer this ability in
> the
> general case, that the feature set is complete enough to describe any
> application of arbitrary complexity, and that any feature in a particular
> case can be known to be possible by analysis before attempting the upgrade
> operation.

It appears that you are trying to develop a generic process whereby the consistency/validity of schema changes can be tested at the schema level, before the data is dealt with. Essentially, a schematic-change exception check between the old and the new and proposed elements of schema change.

Is this correct?

The testing with any live data happens at a later stage. Is this correct?

-- 
Pete Brown
Falls Creek
OZ
www.mountainman.com.au