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#111
 
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Re: What are cons and pros for using IDENTITY property as PK in SQL SERVER 2000? -
12-06-2003
, 02:27 AM
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He is good. I will give him that. We all give short answers. We all get tired of people that are lazy and don't read the manuals. We all are irritated from time-to-time by many things. But it seems that the number of these meangless testosterone contests is getting a bit out of hand. In that case, I suggest you refrain from testosterone contests. My posts have nothing to do with testosterone. When it becomes clear to me that someone is totally beyond help, I add him to my twit filter and move on. Huh? This thread is totally a contest. |
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I love these kinds of threads, if they ever get anywhere. |
person on the other end sees them that way. Perhaps, if you posted something
that might present an intellectual challenge, things might change.
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You are interesting in some ways, but so bizarre in some of your statements: All keys are Surrogate Keys, but Surrogates are not a subset of Keys? |
subset. As I said previously, you do not appear to comprehend relatively
simple english.
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If you don't like someone, including me, please have the courtesy to eiher deal with it off-line or ignore them. There is no requirement that you make everyone else painfully aware of your feelings. I know it may be cathartic but kick a trash can or break something and get over it. I am not sure what feelings you refer to, but I respectfully suggest you project your own feelings onto what you read. You must be a real kick to work with. I thought I was strong-headed, but my goodness. I cannot imagine that anyone could even vaguely interpret anything you say. |
able to comprehend written english. Come to think of it, that is generally
true even for those for whom english was a second or third language.
Sadly, I have finally reached the conclusion that you really do lack the
ability to comprehend or to learn. Since you are totally beyond my help...
toodles!
#112
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How can the generic not be a superset of the specific? What makes you think it has to be a proper superset? How could surrogate keys not be a proper subset of keys! Keys are a superset of surrogate keys and surrogate keys are a superset of keys. They are the same set. |
same thing. That dictionary that seems to be quoted heavily would disagree:
http://dictionary.reference.com/sear...urrogate%20key
http://dictionary.reference.com/sear...andidate%20key
Candidate key being attributes which can be used to identify a row (they say
record, but I refuse to get into the debate on whether a row and a record
are similar or completely different concepts again.)
Surrogate Keys are unique keys that... We have covered that aleady again.
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Natural keys are a proper subset of surrogate keys. |
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| A key is a unique identifying attribute (or attributes) that are used to identify an instance/row of a table. I suppose your SQL background would cause you to think using those terms. A candidate key is an irreducible set of attributes sufficing to uniquely identify each tuple in a relation. That is acually the most unambiguous thing that has been said here in a long |
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| A surrogate key is a key that is a not derived from any other data in the database. Yes, that is the definition you used. A name or a driver's license number or a serial number or any other key is then a surrogate because none of these are derived from any other data. However, I suggest you will find the only accepted definitions of "surrogate" in any dictionary. It is useful to note that ISO has not deemed it worthy of including in the standard vocabularies for IT. http://dictionary.reference.com/search?q=surrogate |
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A surrogate stands for or takes the place of another. Since we cannot stuff actual people or actual things into our databases, our candidate keys stand for them or take their place. A surrogate key is a key, a key may be a surrogate key. I disagree. All candidate keys are surrogates. You have done nothing but assert contrary absurdities without offering any valid justification. To contradict my statement, all you have to do is identify one concrete example of a useful key that is not a surrogate for anything. DNA was a good example. If it was such a good example, how was I able to shred the example so easily? We have identical twins, chimeras, virus and mutation that make DNA inappropriate to use as a candidate key. Quite simply if fails to provide the most basic requirements of a candidate key: namely logical identity. You are correct about identical twins. Fingerprints are a better example. However, mutation of the key does not make it an improper key. Keys change, over time. If the DNA in every cell mutated the exact same way at exactly the same instant of time, you might have a valid point there. Unfortunately, the probability of that happening is somewhat less than likely. |
an identifier, not 100% perfect.
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| A car's VIN number is (though it is a smart key made up of many keys) not a surrogate. A VIN is not a car. It is a surrogate invented by the automobile industry and assigned by the manufacturer. By your definition of surrogate, all data in the database is surrogate. It's not my definition, but the generally accepted definition one finds in the dictionary. |
unnecessarily confusing and I have never seen any other writings to this
effect. I can agree that the entire atabase to represent person, places,
things, or ideas is a surrogate for the real thing, but that is too broad a
way to think when discussing tables and rows.
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| In fact, by your definition, a perfectly normalized data would be 100% surrogate data. A VIN is not a surrogate, however, because it is based upon other information in the database By the arbitrary and meaningless definition you invented to match your absurdities, I suppose that would be the case provided the specific database includes the data upon which each manufacturer derives the VIN. However, one ordinarily uses the accepted term "intelligent key" to describe a candidate key that encodes data one finds in other attributes. The VIN is no less a surrogate for a car. |
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| While there are surrogate keys for each of the different parts, the key itself is not a surrogate, but a description of the thing it is representing. In other words, you agree the VIN is not the thing. It is a surrogate for the thing that describes the thing. You have contradicted yourself. It is only a part of the thing in as much as the thing is represented in the database, not in realityland. Oh, I suppose for those of you who prefer to live in fantasyland that makes an important difference. Yes, in the real world where the sane folks live, a VIN is not a car but stands for a car. No, you apparently lack intelluctual capability to discuss the concept of a key strictly in database terms, not the real world. I agree. I completely lack intelluctual capability--including the intelluctual capability to ignore the real world in support of absurd notions. I do, however, have the intellectual honesty to cede a point when appropriate--as seldom as it is appropriate. It is not absurd. Apparently, it is not absurd in your world to confuse a surrogate for the real thing, but--for the rest of us--your notions are absurd. Not the real thing, the representative of the real thing as it "becomes" |
surrogate for the real thing, but a row is a thing, and it has attributes
which serve a surrogates for the real thing.
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When we model stuff in the database we represent the essense of what makes it what it is. What is the essence of a car? How do we model that essence in the database? What exactly do you mean by essence? Intrinsic or indispensable properties? The most important ingredient? Inherent, unchanging nature? A concentrated extract? One that has an abundance? Something that exists? Every property that can be gathered about that singular thing. When we |
that very car, and only that car. So anything that we can use to describe
the car is helpful (not always possible from the users sense, but it would
be helpful)
Clearly we deal with the changing nature of object in our databases,
otherwise they would not be valueable. Of course the car may or may not be
a single table, due to the process of normalization, just as a customer in a
bank will have a table with slowly changing attributes (like name, that will
likely be in the same primary customer object) and rapidly changing
attributes, like net worth (totals of transactions.) The more information
we have the better our surrogate for the "real" thing is.
What does exist mean? Tangible? Does an idea actually exist? What defines
existance? Obviously anything that can be expressed as a noun exists in
some manner (sounds kind of new agey)
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Sheesh! One minute I am getting criticized for being too terse and the next I am getting criticized for clarifying points to someone who clearly has difficulty with the language. Could you folks try to make up your minds? |
with word that have multiple meanings, inconsistencies, not to mention being
as precise as Pi.
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You will have to forgive me for assuming you did not intend to contradict your previous accusation that I refuse to confine my thoughts to some ethereal otherworldly database realm. After all, worldly does mean relating to or devoted to the temporal (real) world. In case you have any doubt, I am pointing and laughing right now. |
quite a wealthy person. If you had been the lawyer for Benedict Arnold,
this would be the USA, United States of Arnold now
--
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Louis Davidson (drsql (AT) hotmail (DOT) com)
Compass Technology Management
Pro SQL Server 2000 Database Design
http://www.apress.com/book/bookDisplay.html?bID=266
Note: Please reply to the newsgroups only unless you are
interested in consulting services. All other replies will be ignored
#113
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Huh? This thread is totally a contest. For you, I am sure it is a contest. For me, it is not. I love these kinds of threads, if they ever get anywhere. You like contests so you make threads into contests. That doesn't mean the person on the other end sees them that way. Perhaps, if you posted something that might present an intellectual challenge, things might change. |
contest is that you feel me to stupid to be of any competition for your
godlike intelligence.
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You are interesting in some ways, but so bizarre in some of your statements: All keys are Surrogate Keys, but Surrogates are not a subset of Keys? I don't know what you find bizarre about noting that a superset is not a subset. As I said previously, you do not appear to comprehend relatively simple english. Agreed. Nor do I understand complex English (not sure what english is, |
errors)
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Sadly, I have finally reached the conclusion that you really do lack the ability to comprehend or to learn. Since you are totally beyond my help... toodles! |
concepts like you do, rather than everyone else who has participated in the
discussion.
--
----------------------------------------------------------------------------
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Louis Davidson (drsql (AT) hotmail (DOT) com)
Compass Technology Management
Pro SQL Server 2000 Database Design
http://www.apress.com/book/bookDisplay.html?bID=266
Note: Please reply to the newsgroups only unless you are
interested in consulting services. All other replies will be ignored
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