Re: 3vl 2vl and NULL
Date: 17 Feb 2006 06:26:11 -0800
Message-ID: <1140186371.199652.117130_at_g43g2000cwa.googlegroups.com>
FrankHamersley wrote:
> dawn wrote:
<snip>
> > Similarly, the query language can be used to get what is called a
> > select list or saved list of keys for the selection aspect of what to
> > udpate.
>
> So you actually save the list of targets?
Typically only in memory, although for some analytical reporting a list might be saved much longer.
> What happens in a TP
> environment where it is a moving feast?
<snip>
> OK - what is the risk profile of less experience people writing ad hoc
> stuff. Is it easy for them to generate run away trains in a view that
> takes a lot of compute to resolve or are there safety nets?
> > During all those years of companies working hard to get end-user
> > reporting, MV end-users were either churning out reports and ad hoc
> > queries or asking their VARs or IT shops for new ones and getting a
> > fast turn-around on their requests.
> >
> > [Anecdote: I moved from an IMS COBOL shop with a significant backlog
> > for reports to an MV shop with no backlog, zero, zip, for any
> > reporting. It was very enlightening.]
>
> No doubt - COBOL would not be my lang of choice however!
> >>- is this an important additional phase in the design phase or is it
> >>simple to retrofit on demand?
> >
> > simple, but not something you typically pass to an end-user to do since
> > it adjusts the schema (which is descriptive and not prescriptive, so
> > the risk is to other queries).
>
> What happens to these view if cardinality is changed - perhaps even
> arbitrarily - are they "self healing" or do they require maintenance?
Self-healing. The top value in each list is on the first line, with subsequent values below it.
<snip>
> Does it get deployed in multi-tier apps much - the one I saw was single
> tier.
These days, most definitely. Since it has been around > 35 years, there is still a lot of green-screen out there.
<snip>
> >>Is it easy to dump (aka bcp out) to another (SQL?) environment for ad
> >>hoc queries, routine reporting or data warehousing?
> >
> > A techie would say that it is easy and I have advised and assisted in
> > such efforts many times, but find it not altogether satisfying. Once
> > you normalize the data, your solution is no better than the average SQL
> > implementation so you lose the charm (e.g. ease in working with
> > multiple 1:M's in queries) and have the added pain of such things as
> > switching from 2VL to 3VL, for example (equating a Pick null with a SQL
> > null does not typically work well). Those for whom I have recommended
> > this approach for their specific requirements have told me it is
> > working well for them, however.
>
> Is there no other way to leverage these BI products?
Most people do downloads into Excel and elsewhere. There is a lot of
variety and creativity in how this is done, but nothing standardized.
<snip>
> There are no silver bullets! It reminds me of a prediction that I made
> when I first started in IT. I suspect I would need a different job in
> about 5 years because at the rate IT was expanding by that time
> programme writing programmes would make me as a hacker redundant. Of
> course I was coding in ASM at the time and we had been exposed to
> Modula-2 plus reviewed the Ada spec in the course, and it seemed like a
> formality. Of course I was wrong - so I gave trying to predict and just
> look for empirical data - which is why I see the market share as
> confirming the RM over the MV.
I understand the reasons for choosing that metric, given the lack of others. It is surely an indicator of something, but...
> Anything that upsets this apple-cart is
> going to be novel, not a throwback - yikes, another prediction!
I agree. If there is a focus on development productivity, the next big thing in data models will look more like PICK (e.g. XML, JSON) than RM. That's my prediction.
<snip>
> OK - I accept that RM forms are not always instantly appealing to a
> casual observer. However I still rate the solidity of its foundations
> as more than adequate compensation, and once it is under your skin (i.e.
> it all clicks) then you hardly even credit that a "problem" exists.
Yes, and familiarity is a reason to stick with something that works too. At an industry level, we have SQL under our skin.
<snip>
> Look closely at the world around you. I just recently saw a .Net crash
> panel on a customer facing cash register screen. The operator just
> shrugged and rebooted the app - no problem, what problem, nothing to
> see, move along!
good anecdote
<snip>
>
> Thanks for being candid about Picks top 5 shortcomings - your
> co-conspirators prolly think you are related to Judas Iscariot by blood :-).
Cheers!. --dawn Received on Fri Feb 17 2006 - 15:26:11 CET