define composite primary key with more than 900 bytes

Question

define composite primary key with more than 900 bytes

anbillava

Ten Centuries

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April 15, 2010 at 12:44 pm

#221332

I have a situaton where in i need to define unique combination of some of the columns I tried defined it using composite primary key. But I have more than 70 columns and this is exceeding 900 bytes. Anybody has any solution. Please let me know.

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Lynn Pettis SSC Guru Points: 442447 More actions · Answer 1

anbillava (4/15/2010)
I have a situaton where in i need to define unique combination of some of the columns I tried defined it using composite primary key. But I have more than 70 columns and this is exceeding 900 bytes. Anybody has any solution. Please let me know.

Why do you need a composite key made up of more than 70 columns? Something doesn't sound right here.

anbillava Ten Centuries Points: 1146 More actions · Answer 2

I have situation where in if user enters same data then i need throw him a error message depending up on the primary key violation. Each row in the table should be unique against the other. Any other solution is appreciated.

Thanks

GSquared SSC Guru Points: 260824 More actions · Answer 3

You could assign a unique key to a checksum of all of the columns.

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anbillava Ten Centuries Points: 1146 More actions · Answer 4

Thanks for the reply.

CAn you please tell me how to do that ?

SQLRNNR SSC Guru Points: 281324 More actions · Answer 5

Try this article.

http://www.mssqltips.com/tip.asp?tip=1023

Jason...AKA CirqueDeSQLeil
_______________________________________________
I have given a name to my pain...MCM SQL Server, MVP
SQL RNNR
Posting Performance Based Questions - Gail Shaw[/url]
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Lynn Pettis SSC Guru Points: 442447 More actions · Answer 6

So what you are saying is that in this particular table, there is no candidate key that could serve as a primary key?

Lynn Pettis SSC Guru Points: 442447 More actions · Answer 7

Seems to me that this article may also help, http://qa.sqlservercentral.com/articles/Data+Warehouse/69679/.

anbillava Ten Centuries Points: 1146 More actions · Answer 8

Is that link tells me about defining unique key for checksum of mulitple columns.

I did not understand how that works ?

Do i need to check table for the duplicate row using checksum function or blind entry of new data which is duplicate will throw a vilolation ?

anbillava Ten Centuries Points: 1146 More actions · Answer 9

No. There is no candidate key which can replace this.

Lynn Pettis SSC Guru Points: 442447 More actions · Answer 10

Actually, anything we tell you is simply a shot in the dark. We have no idea what you are trying to do, or what type of data is being stored in this (currently) nebulus table in which the primary key appears to be every column in the table.

Where and how is the data being inserted into the table? Is the data load from a file or entry from an application?

anbillava Ten Centuries Points: 1146 More actions · Answer 11

CAn anybody help me in defining checksum column ?

MAny Thanks

Lynn Pettis SSC Guru Points: 442447 More actions · Answer 12

Have you looked up CHECKSUM in BOL (Books Online)? If not, try this.

anbillava Ten Centuries Points: 1146 More actions · Answer 13

Hi all,

I am able to define checksum column and do the job .

Thanks to all.

Anand

SQLRNNR SSC Guru Points: 281324 More actions · Answer 14

You're welcome. Hope it works out for you.

Jason...AKA CirqueDeSQLeil
_______________________________________________
I have given a name to my pain...MCM SQL Server, MVP
SQL RNNR
Posting Performance Based Questions - Gail Shaw[/url]
Learn Extended Events