Re: Another view on analysis and ER

From: Jon Heggland <>
Date: Fri, 07 Dec 2007 10:08:35 +0100
Message-ID: <fjb2jb$kpb$>

Quoth Jonathan Leffler:
> Now, consider what else is stored in the database. For the analysis of
> isotopes, the atomic number is the important key - the different
> isotopes of hydrogen all share the same atomic number, but have
> different names (deuterium and tritium) even though chemically they are
> all hydrogen.
> For the analysis of chemical compounds, it is much more familiar to use
> the element symbol - more people have come across H2O and CO2 than are
> familiar with 1/2, 8/1 and 6/1, 8/2 (where I'm using atomic number /
> multiplicity in the second notation). I'm glossing over some notational
> inconveniences (consider the relational representation of your old
> friend C2H5OH, for example), but the point remains - for some purposes,
> the better key to use is atomic number and for other purposes, the
> better key to use is element symbol.
> Which key to use is a logical issue here, isn't it?

Which key to use for what is definitely a logical issue, but designating one as primary does not mandate how it is used. I'm not sure if you are agreeing or disagreeing with me..?

Received on Fri Dec 07 2007 - 10:08:35 CET

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