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Primary Keys


Primary Keys

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dwain.c
dwain.c
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Comments posted to this topic are about the item Primary Keys


My mantra: No loops! No CURSORs! No RBAR! Hoo-uh!

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?
Since random numbers are too important to be left to chance, let's generate some!
Learn to understand recursive CTEs by example.
Splitting strings based on patterns can be fast!
My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables
Tom Thomson
Tom Thomson
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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. :-P

Tom

bitbucket-25253
bitbucket-25253
SSCrazy Eights
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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. :-P


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

Before posting a performance problem please read
rals
rals
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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.

Smile

Regards,
Rals
.

dwain.c
dwain.c
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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!

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?
Since random numbers are too important to be left to chance, let's generate some!
Learn to understand recursive CTEs by example.
Splitting strings based on patterns can be fast!
My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables
Koen Verbeeck
Koen Verbeeck
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Easy one for Monday, thanks!


How to post forum questions.
Need an answer? No, you need a question.
What’s the deal with Excel & SSIS?
My blog at SQLKover.

MCSE Business Intelligence - Microsoft Data Platform MVP
Sreepathi1987
Sreepathi1987
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Than you for the good week start.........!!!
Toreador
Toreador
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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
Jeff Moden
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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.
If you think its expensive to hire a professional to do the job, wait until you hire an amateur. -- Red Adair

Helpful Links:
How to post code problems
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Stewart "Arturius" Campbell
Stewart "Arturius" Campbell
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Good reminder, Thanks Dwain

If anyone comes even close to that limit, however, I would seriously propose a remedial database design course, with a healthy heaping of normalisation thrown in for good measure...:-P

____________________________________________
Space, the final frontier? not any more...
All limits henceforth are self-imposed.
“libera tute vulgaris ex”
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