Re: More on lists and sets
Date: Thu, 23 Mar 2006 13:21:19 GMT
Message-ID: <jhxUf.5689$8G2.2014_at_trndny01>
"Brian Selzer" <brian_at_selzer-software.com> wrote in message
news:j%tUf.49721$F_3.48160_at_newssvr29.news.prodigy.net...
>
> If order is unimportant, then transformation back and forth between a list
It's trivial in the sense that no non trivial information is lost. But it
may not be non trivial in the sense of affecting programmer productivity.
According to the MV enthusiasts, their data structure is more conducive to
presenting data "the way people think". I'm not convinced, when it comes to
the interface between the database and the programs that manipulate data.
However, there is another context, where NFNF data is clearly easier on the
eye than 1NF data.
Here it is: It's a window with three frames inside it. The first frame is
fixed, displaying the data that occurs once per entity. Each of the two
remaining frames shows a scrolling list, for related data that can occur
multiple times.
I'm kind of sick of pizza right now, so here's my example:
The window is of applicants for a job. The first subframe is for data like
First Name, Last Name, SSN, etc. that occurs once per applicant.
The first list is for skills the applicant possesses, with data about
number of months of experience, and certification (yes or no). Each skill
occupies a line in the frame. If there are more skills than fit in the
frame, scrolling happens.
The second list is for previous jobs the applicant has held. (Start date,
end date, job title, etc.). There's one line for each job. Again, if the
whole list won't fit in the frame, scrolling happens.
If the applicant is still employed the last "end date" is left blank (Hah!
Take THAT D&D!)
Clearly the two lists can expand arbitrarily. (while the relationship
between skills and previous employers might exist, it might not be relevant
for this screen.)
But it's not very easy from a programming perspective. And programmers
would be more productive if it were easy.
> and a bag is trivial.
And that to me is the difference between a "file" and a "database" in a nutshell. Received on Thu Mar 23 2006 - 14:21:19 CET