Re: Examples of SQL anomalies?

On 7 juil, 17:28, "Brian Selzer" <br..._at_selzer-software.com> wrote:
> "Cimode" <cim..._at_hotmail.com> wrote in message
>
> news:b6313a3d-a07c-40d7-859c-6c70db4fa0c9_at_f63g2000hsf.googlegroups.com...
>
>
>
> > On Jul 7, 1:30 am, "Brian Selzer" <br..._at_selzer-software.com> wrote:
> >> "Cimode" <cim..._at_hotmail.com> wrote in message
>
> >>news:623888cb-7e35-4aaf-a496-1654f8fed040_at_k37g2000hsf.googlegroups.com...
>
> >> > On 6 juil, 17:46, "Brian Selzer" <br..._at_selzer-software.com> wrote:
> >> >> "Cimode" <cim..._at_hotmail.com> wrote in message
>
> >> >>news:f4a29563-3e69-4d50-a3d8-07d434aac374_at_27g2000hsf.googlegroups.com...
>
> >> >> > On 6 juil, 15:43, "Brian Selzer" <br..._at_selzer-software.com> wrote:
> >> >> > [Snipped]
> >> >> >> >> The users know what the data is supposed to mean. The system
> >> >> >> >> hasn't a
> >> >> >> >> clue.
> >> >> >> > I do not understand how you place system and people on the same
> >> >> >> > standpoint. Don't you believe in need-to-know basis?
>
> >> >> >> What has that to do with it?
> >> >> > Everything. Why do you want to place the burden of data
> >> >> > interpretation
> >> >> > on people at run time. What is the point designing systems to
> >> >> > present
> >> >> > information to people if they have to spend hours guessing what it
> >> >> > means?
>
> >> >> I would place the burden of data interpretation on people because it
> >> >> is
> >> >> only
> >> >> people that can interpret data.
> >> > OK but do they need to do it at run time. What would be the point of
> >> > design then?
>
> >> In some cases, yes, they need to do it at run time. With an unlimited
> >> budget of time and money, you can handle every possible exception in
> >> code,
> >> but back here in the real world, you can't waste precious resources on
> >> something that seldom occurs, so you just print out an exception report
> >> and
> >> provide the means for the users to deal with them (if it doesn't already
> >> exist).
> > Who says design should be unlimited? Design simply sufficient to
> > handle most cases and it should correct on RM standpoint. What about
> > time wasted on poor design?
>
> From what I've seen, poor design usually translates to inadequate design.
> If you don't spend enough time on design, you end up reinventing the wheel
> halfway through the implementation, and it ends up costing upwards of double
> the budget.
How about the idea that poor(inadequate if you feel better with this term) design = using NULLS

> >> >> Why would they have to spend hours? Hopefully any system would
> >> >> present
> >> >> enough complete information to obviate most guesses, but for the rest,
> >> >> given
> >> >> a choice between being given a potentially wrong answer and being told
> >> >> that
> >> >> the information is incomplete, I (and most people I know) would prefer
> >> >> the
> >> >> latter, even if it required a little extra effort on my part.
> >> > But then, following this logic and the 8 item weigth example, the
> >> > system would then require the information that the sum is relevant
> >> > only up to 8 items to be available to people for them to make
> >> > *educated* guesses. Don't you think that makes things more
> >> > complicated? Most people I know would tell you, you did a poor design
> >> > job and that they don't need this irrelevant information.
>
> >> The information is already available. If SUM returned an indeterminant
> >> result, then the user should be able to issue additional queries
> >> qualified
> >> with something like, WHERE weight IS NULL or WHERE weight is NOT NULL, in
> >> order to find out why the result was indeterminant. It certainly isn't
> >> rocket science.
What information is available ? The information fact that it is not correct(suspect) ? How is it already available ?

What interest in building systems that bring the information that the system is not reliable and impose on people a two step that would force them to re-interpretate and force them to permanently using NOT NULL/IS NOT NULL. Rocket science is understanding how is that simpler than simply taking the NULLS out of the equation and not have to deal with all this.
> > But what user are you refering the end user or the designer? Should
> > an application end user have to know about IS NULL / IS NOT NULL?
>
> Both, and neither. The user could be the designer, or an application
> developer, or the user could be an end-user writing a Crystal Report or
> integrating a spreadsheet. I would think that in order to integrate a
> spreadsheet, the end-user would have to know about IS NULL / IS NOT NULL if
> any of the columns in any of his queries can have NULLs.
So, basically the end user is intended as designer on a per use and per application basis? Don't you believe this would leave the meaning of information open to designer's interpretation? Received on Tue Jul 08 2008 - 01:19:27 CEST