Re: Conceptual, Logical, and Physical views of data

David Cressey wrote:
> My introduction to databases, back in the 1980s, was, in part, by way of
> Martin. I got this description of multiple views of data: the conceptual,
> logical, and physical views.
>
> The conceptual view of data: the data as seen by the subject matter expert.
> The meaning of each of the values, in context, is part of the subject matter
> expert's domain. Database structure is not the domain of the SME, in that
> role.
>

the problem, as i've seen it in large/mainframe organizations (much less so in unix/database VAR software whose clients know they're buying a better way to do their business), is that SMEs (certainly those whose working lives are younger than 1-2-3) seldom are capable of thinking beyond the spreadsheet view of data. even if the database modeler/designer can get to a 3NF structure, the SMEs still insist on seeing all that repeated data in their columns.

there is a really famous computer guy (whose name i can't recall, of course) who laments that the quality of computer systems is directly and inversely correlated with PC incursion into the workplace due to just the above. there is a study every now and again since about 1982 which shows that the PC and its network has *decreased* workplace productivity; in no small part due to such activities as spending an hour deciding just which font should be used.

i believe it can be proved (not that i can personally) that there exists   a NF from which any non-normalized view can be reconstructed. just to satisfy those SMEs who can't figure out their own data.

BobTheDataBaseBoy Received on Tue Aug 30 2005 - 19:02:08 CDT