Prime Attributes

Question

Prime Attributes

TomThomson

SSC Guru

Points: 104773
More actions
October 11, 2011 at 9:46 pm

#249158

Comments posted to this topic are about the item Prime Attributes
Tom
October 12, 2011 at 12:36 am

This was removed by the editor as SPAM

Viewing 15 posts - 1 through 15 (of 18 total)

You must be logged in to reply to this topic. Login to reply

DugyC Hall of Fame Points: 3804 More actions · Answer 1

Great question Tom, I can say that as I surprised myself by getting the right answer 😀

_____________________________________________________________________
[font="Comic Sans MS"]"The difficult tasks we do immediately, the impossible takes a little longer"[/font]

CoolCodeShare SSCrazy Points: 2584 More actions · Answer 2

It is very good question. I was sure about the half part. Got to revise lots of things.

Basics matter!!

Best Regards,

Sudhir

spaghettidba SSC Guru Points: 105732 More actions · Answer 3

Darn! I don't know why, but I checked "has a different value on each row".

Nice question, Tom.

-- Gianluca Sartori

palotaiarpad SSCertifiable Points: 5617 More actions · Answer 4

Hmmmm.

I used the same source (http://en.wikipedia.org/wiki/Database_normalization) i hope (because the link provided on the result page isn't existing), and there is a definition: A prime attribute, conversely, is an attribute that does occur in any candidate key.

But is it wrong then?

OzYbOi d(-_-)b SSCarpal Tunnel Points: 4054 More actions · Answer 5

Thanks Tom. (open up QotD and knew immediately who wrote it! 😛 )

After your question last week I did some revision so was a little better prepared to tackle this one today. Certainly making me flex the ol' brain in areas that are not as regularly flexed! 🙂

OzYbOi d(-_-)b SSCarpal Tunnel Points: 4054 More actions · Answer 6

palotaiarpad (10/12/2011)
Hmmmm.
I used the same source (http://en.wikipedia.org/wiki/Database_normalization) i hope (because the link provided on the result page isn't existing), and there is a definition: A prime attribute, conversely, is an attribute that does occur in any candidate key.
But is it wrong then?

The context here is that Non-Prime attribute does not occur in any candidate key, so CONVERSELY, a PRIME attribute does occur in any [but not all] candidate keys

The statement is correct, however the WIKI definition could certainly be worded a little better...

Rob Schripsema SSCertifiable Points: 7469 More actions · Answer 7

Too bad half right doesn't count for anything...

Good question, Tom!

Rob Schripsema
Propack, Inc.

Ron McCullough SSC Guru Points: 63877 More actions · Answer 8

Nice question. Took much too long to shake the cobwebs out of my brain.

If everything seems to be going well, you have obviously overlooked something.

Ron

Please help us, help you -before posting a question please read[/url]
Before posting a performance problem please read[/url]

charles evans SSCommitted Points: 1865 More actions · Answer 9

Oops, mistook the word "every" for "any" in the candidate key answers.

Trey Staker SSCarpal Tunnel Points: 4796 More actions · Answer 10

Thanks for the question Tom. Your questions always make my brain hurt.

---------------------------------------------------------------------
Use Full Links:
KB Article from Microsoft on how to ask a question on a Forum

TomThomson SSC Guru Points: 104773 More actions · Answer 11

palotaiarpad (10/12/2011)
Hmmmm.
I used the same source (http://en.wikipedia.org/wiki/Database_normalization) i hope (because the link provided on the result page isn't existing), and there is a definition: A prime attribute, conversely, is an attribute that does occur in any candidate key.
But is it wrong then?

Not the same page, but one just as good; I'm not sure what happened to that reference, it was cut and paste from my browser address bar. The definition on the wikipedia page you found contained a strange use of "any": "any" meaning "some". This is sort of logical but is a very unusual usage, so people get confused when "any" is used like that, and sometimes think it means "every". That wikipedia page has now been corrected and uses "some" instead of "any" which should be clearer.

The writer of the original definition on the wikipedia page can be excused because he probably though that misinterpretation of that "any" would be avoided by that little word "conversely", which is saying that "prime" is the converse of "non-prime" which is defined immediately above (and the converse of "it isn't in any candidate key" is "it is in some candidate key") but it's better to avoid unusual usage and aim for clarity in something like wikipedia.

Tom

palotaiarpad SSCertifiable Points: 5617 More actions · Answer 12

Thanks, now it's clear that my english has to be improved. 😀

Vinay Kumar SSCertifiable Points: 6099 More actions · Answer 13

Good question tom

Thanks
Vinay Kumar
-----------------------------------------------------------------
Keep Learning - Keep Growing !!!