Re: [AM] Database "refactoring" effort question

At 05:20 PM 2/3/2004 -0500, you wrote:
>(responding to Scott)
> >
> >>My point is that you are creating two columns of *new* data.
> >
> > Where is the new data coming from?  If I had one column with
> > "Ambler Scott" in it and new have two columns, one with "Ambler"
> > and one with "Scott" there isn't any new data. This is the extent
> > of the split column refactoring.  Anything you do beyond that is
> > something else.
>
>IF, and it hasn't yet been decided, that's what you do, then
>the new data is generated from the old data plus a bit (or
>more like 7 bits as I recall my Information Theory) of
>extra information.  It takes 1 binary digit to say whether
>the front or back part of the original name goes into the
>Surname field, and it takes around 6 binary digits of
>information to say where to split the original data field.
>This information needs to come from somewhere.

This information would be embedded in the refactoring code.

<snip>
> >>   Yet there is nowhere in the
> >> system that contains all the data needed to create the new
> >> data from what is already there.
> >
> > Why not?  Source data + rule ==> refactored data.
>
>The rule isn't in the system yet.

Yes, so there arguably is a change in the semantics at a theoretical 
level.  I was pretty clear in my definition of database refactoring that I 
wasn't interested in issues like this, that I wanted to focus on practical 
issues.



> > Yes, you may also decide to go in by hand at some point
> > and clean up the dirty data, but that's above and beyond
> > the refactoring.
>
>You can still only get the data so clean before you need to
>contact the individuals whose names you are trying to
>decipher.

Yes, data cleansing rarely works out perfectly.

><snip>

- Scott


====================================================
Scott W. Ambler
Senior Consultant, Ronin International, Inc.
www.ronin-intl.com/company/scottAmbler.html

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