X-Received: by 10.236.26.108 with SMTP id b72mr17785138yha.33.1422895861516; Mon, 02 Feb 2015 08:51:01 -0800 (PST) X-Received: by 10.50.142.36 with SMTP id rt4mr160212igb.2.1422895861418; Mon, 02 Feb 2015 08:51:01 -0800 (PST) Path: news.cambrium.nl!textnews.cambrium.nl!feeder3.cambriumusenet.nl!feed.tweaknews.nl!195.208.113.2.MISMATCH!goblin2!goblin1!goblin.stu.neva.ru!bm13no5333952qab.0!news-out.google.com!qk8ni19963igc.0!nntp.google.com!hl2no7749348igb.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.databases.theory Date: Mon, 2 Feb 2015 08:51:00 -0800 (PST) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=101.175.1.237; posting-account=bFMNewoAAAAHC6b_JPlV7XvI31zIuG5T NNTP-Posting-Host: 101.175.1.237 References: <61044dae-51c9-43d4-87f9-1e12e0e3b15e@googlegroups.com> <0f9dea1d-36e1-4378-93a4-cb790a57c893@googlegroups.com> <4fcace2f-e767-4beb-8c54-0a7543b2fd30@googlegroups.com> <63393ec9-6afb-4ee8-b2c7-ae0186d4e227@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Why are [Database] Mathematicians Crippled ? From: Derek Asirvadem Injection-Date: Mon, 02 Feb 2015 16:51:01 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Xref: news.cambrium.nl Jan Let's see if we can pick up the pace a bit. So I have established, under Roman Dutch Law, in civilised countries that a= re not held hostage by gypsies, tramps, and thieves, the "professor" is com= mitting three frauds, worthy of a medium prison sentence, and the authors a= re committing one great fraud, and the sentence is much greater, execution. > On Tuesday, 3 February 2015 02:09:05 UTC+11, Derek Asirvadem wrote: >=20 > Now the unchanging law is, since you are not aware of it, since 1970, Cod= d's definition of Third Normal Form. From memory (ie. I am happy to be cor= rected, but I expect any errors to be minor, unworthy of argument): > ____ "Every non-key attribute is Functionally Dependent on the Key, the w= hole Key, and nothing but the Key" In case you theoreticians are not aware, it follows from the above, for us = undamaged humans, that "Key" identified, is a key issue. Without the Key, = there is nothing for the attributes to be, or not be, Functionally Depende= nt upon. Therefore it is impossible to contemplate a Functional Dependency= , unless and until one is choosing a Key. The Key does not have to be fina= l, just an attribute set that is honestly being considered as a Key.=20 1. Post-choice of a Key, the FDs are used purely as a verification method. = Very fast, very clera. 2. During the choosing of a Key, FDs are used deterministic method. A bit = more work, but very clear. 3. Prior to choosing a Key, FDs are pure conjecture, because there is nothi= ng for the attributes to be Functionally Dependent upon. So even if they i= dea was contemplated, it really should be named something else, not FDs. T= o the extent that the theoreticians use the term for [3], it is fraud, conf= usion at best. [3] has no clarity at all, it is confusing to most people to whom it is giv= en. It is slow, until such time as a meaningful goal is given. So in the physical universe of practitioners, only [1] and [2] exist. [3] = is unknown, and if considered, quite laughable, pointless, needless. Then there are a few practitioners, such as yours truly, who know a tiny bi= t about what theoreticians do in their MMM workshops. They have figured o= ut, that by trying all the permutations of the possible "FDs", on all the a= ttribute sets and subsets, such that when certain magical mystical combinat= ions occur, woohoo, they have determined a "key". Marvellous. Wonderful. Give the magician a gold star and a pointy hat. One more elephant hair has= been determined, but they are still clueless about the elephant. Codd gave us the definition of a Key: "it is made up from the data, a subse= t of the attributes that uniquely identify the row (tuple)" Can any of you give me an example of where any company on the planet uses 1= 's and 2's or x's and y's as attribute values ? Right. So the fact is, that the key-determination-via-non-functional-dependency me= thod is good for nothing in the physical universe. But there is a learning= value. If the examples used real data values, instead of 1's and 2's, the kids mig= ht learn something. Otherwise it is a Japanese puzzle for 3-year-olds, usi= ng 1's and 2's instead of 1-to-9's. ---- The "professor" is trying to teach that[3]. Not [1], not [2], but [3]. Bu= t the title is [1]. If he was teaching [3] properly, then he would introdu= ce and explain what the concept is, then he would teach it. He doesn't. H= e launches into the most idiotic, useless, meaningless use of FDs, without = explaining a thing, without teaching [1], then[2], then: oh, btw, here is a= neat trick if you ever are in the position where you cannot determine the = key, here is [3]. So the evidenced facts are (check the video), he is teaching [3] with no in= troduction or explanation, under the title of [1]. Hence my initial comments re the hairs on his head, the fish in the sea. Hence my initial comments: he is clueless *about* the subject; he is cluele= ss about *how to teach* the subject; but he is teaching it anyway, under a = title that is well-established. Fraud count number four. And again, if alien magicians wrote books, that instructed him to teach FDs= like this [3][1][2], backwars and upside-down, severe fraud count two agai= nst them. Fifty lashes before the hanging, and hanging upside-down. I hope I have bridged the chasm, at least in this one small subject. The l= evel of understanding, the distance between the theoreticians in this field= , and ythis field, is like the Grand Canyon. Cheers Derek