Primary Keys

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Primary Keys

Dwain Camps

SSC Guru

Points: 86908
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July 28, 2012 at 12:35 pm

#392850

Comments posted to this topic are about the item Primary Keys
My mantra: No loops! No CURSORs! No RBAR! Hoo-uh![/I]
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St
July 30, 2012 at 5:24 am

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TomThomson SSC Guru Points: 104773 More actions · Answer 1

Nice easy unambiguous question.

A restful finish to to the week (for some), and a pleasant start to the week for others.

Published a little before its time, I guess, as it's the day after tomorrow's question. 😛

Tom

Ron McCullough SSC Guru Points: 63877 More actions · Answer 2

L' Eomot Inversé (7/28/2012)
Nice easy unambiguous question.
A restful finish to to the week (for some), and a pleasant start to the week for others.
Published a little before its time, I guess, as it's the day after tomorrow's question. 😛

Nah just right if you use that unsupported command DBCC TIMEWARP

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]

ralm Hall of Fame Points: 3156 More actions · Answer 3

Index has the limitation of 16 key columns, primary key can be either clustered or non-clustered. So it can also have only 16 columns. I guessed the answer as above.

🙂

^{[font="Verdana"]Regards,
Rals[/font].}

Dwain Camps SSC Guru Points: 86908 More actions · Answer 4

Tom, Bitbucket and Rals - Thanks for dropping by and giving it a shot.

I believe that the limitation on columns participating in an INDEX is the same as for the primary key, so you were right to guess that Rals.

My mantra: No loops! No CURSORs! No RBAR! Hoo-uh![/I]
My thought question: Have you ever been told that your query runs too fast?

My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.

Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St

Koen Verbeeck SSC Guru Points: 259085 More actions · Answer 5

Easy one for Monday, thanks!

Need an answer? No, you need a question
My blog at https://sqlkover.com.
MCSE Business Intelligence - Microsoft Data Platform MVP

Sreepathi1987 Default port Points: 1425 More actions · Answer 6

Sreepathi1987

Default port

Points: 1425

July 30, 2012 at 1:41 am

#1519016

Than you for the good week start.........!!!

Toreador SSChampion Points: 11358 More actions · Answer 7

Got it wrong as there's no mention of a limit in the Primary Key or Create Table sections of BOL.

Anyone who even approaches the limit should be sent on a training course anyway 🙂

Jeff Moden SSC Guru Points: 1003857 More actions · Answer 8

I was pretty sure of the answer but went to check just to be absolutely sure because I've never gotten close to the limit. It just absolutely fascinates me that this little bit of very important "trivia" ISN'T covered under the constraints, primary key, or CREATE TABLE sections of BOL.

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

Thomas Abraham SSChampion Points: 10761 More actions · Answer 9

Jeff Moden (7/30/2012)
I was pretty sure of the answer but went to check just to be absolutely sure because I've never gotten close to the limit. It just absolutely fascinates me that this little bit of very important "trivia" ISN'T covered under the constraints, primary key, or CREATE TABLE sections of BOL.

Same reaction, both to the question and BOL. Also, wasn't there a recent question that was tangentially related to this? Something about large data types in an index?

[font="Verdana"]Please don't go. The drones need you. They look up to you.[/font]
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