Re: 3vl 2vl and NULL
Date: Wed, 01 Feb 2006 01:11:32 GMT
Message-ID: <8VTDf.232537$V7.214490_at_news-server.bigpond.net.au>
dawn wrote:
> Frank Hamersley wrote:
[Quoted] >>dawn wrote: >>>Frank Hamersley wrote: >>>>dawn wrote: >>>>>Frank Hamersley wrote: >>>>>>dawn wrote: >>>>>>>Frank Hamersley wrote: >>>>>>>>dawn wrote: >>>>>>>>>Frank Hamersley wrote: >>>>>>>>>>dawn wrote: >>>>>>>>>>>Frank Hamersley wrote:
[....]
>>>>>>>>I disagree - there are measurable gains to be had in adopting the RM for >>>>>>>>the storage engine that, >>>>>>> >>>>>>>Can you point me to some emperical data that indicates that? And even >>>>>>>if that were the case, are there corresponding gains to making the RM >>>>>>>the interface between dbms and humans (developers)? >>>>>> >>>>>>I have no empirical data (for or against). >>>>> >>>>>What are these "measurable gains" then? What do they measure? Who has >>>>>done such measuring? >>>> >>>>First, the most obvious gain is a repeatable capability to consistently >>>>disseminate and/or interrogate a large and complex dataset amongst many >>>>people all with varied interests and in so doing avoid the need to >>>>inculcate them with all the various nuances a 2VL programmer might dream >>>>up to persist each item of data. >>> >>>Now that has GOT to be tough to measure. >> >>Perhaps so - the fact that it is feasible at all is reassuring!
>
> How do you know this to be a fact?
[Quoted] Allowing for Nietzsche et al existentialist risk in my assessment - simply because they keep loading me up with new work after I complete each assigned task.
[Quoted] >>>>After factoring in a life cycle and >>>>unavoidable changes in staffing these nuances can become debilitating. >>> >>>I've worked with plenty of systems that are not based on the RM with >>>code > 20 years old and counting. So, this measurement, too, could be >>>difficult to quantify. I've looked at possibilities for what might be >>>quantifiable and nothing looks very straight-forward. I know I don't >>>have emperical data related to bang for the buck or any other metric >>>for non-SQL or non-RDBMS compared to SQL-DBMS's, but I sure have seen a >>>lot of claims about how the RM has been shown to be superior to all >>>other models. You just claimed that there were measureable gains with >>>the RM. I'm just wondering what these measurements are and how I can >>>duplicate whatever experiment these come from. >> >>In the strictest sense there prolly isn't any. Nobody in IT conducts >>blind trials or uses statistical methods to assess outcomes - about the >>only quotable statistics seems to be the project failure rate exceeds 50%!
>
> This is where there could be some measurement. My hunch is that there
> are fewer project failures in the MV world than in the SQL-DBMS world.
[Quoted] The WTF presentations suggest otherwise, although as Murphys Law would have it todays gem is SQL related!
> However, then folks will argue that you pay the price down the road in
> MV (which I do not see to be the case). Measurements would need to
> measure the total cost of developing and maintaining systems, but also
[Quoted] > some measure to ensure the systems are effective for the users.
[Quoted] Yup - but IT isn't about waiting around for epidemiological studies to complete.
> I'll go out on a limb and say that it is unlikely that a development
> team working with a SQL-DBMS tool would end up writing the same system
> from the user perspective as a team working with an MV system. The
> data modelers for the SQL-DBMS tool will work to avoid multivalues so
> they don't have to form new tables for short lists that don't seem too
> important, for example. I've seen more FormerNames fields in MV
> systems, collecting all former names as they become such in cases where
> it would not be warrented in a SQL-DBMS system -- a single-valued
[Quoted]
> "Maiden Name" attribute (or whatever is deemed politically correct now)
> is more likely.
[Quoted] Interestingly your example would be a non-event if support for the "time varying" (temporal) aspect of Codds laws were provided in the various [Quoted] main stream SQL implementations. I guess temporality will never become integral in the non RM space, and at the current rate of progress in RM research not in the SQL standard very soon to boot!
[..]
Cheers, Frank. Received on Wed Feb 01 2006 - 02:11:32 CET