Identity column concurrency

Question

Identity column concurrency

Hardy21

SSCrazy Eights

Points: 9708
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October 21, 2010 at 12:22 am

#230656

Suppose I have a tableA with primary key has Identity column. In this table multiple user inserts the data simulatenously so because of Indetity column it may create Primary key violation error. If I create Intead of insert trigger to check value is unique then it creates performance issue.
I would like to know what is the best way to handle this situation so user does not receive primary key violation & still we are able to insert the data?
Thanks

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Ian Scarlett SSC-Insane Points: 23197 More actions · Answer 1

In this table multiple user inserts the data simulatenously so because of Indetity column it may create Primary key violation error.

What makes you say this?

Having an identity column as the primary key should not cause duplicates, no matter how many users are simultaneously inserting data into the table.

Bhaskar Basak SSC Eights! Points: 967 More actions · Answer 2

Do not Insert data with IDENTITY_INSERT ON option. Then SQL Server take care of concurrency, it is guranteed that there will not be any duplicate id in Identity column.

Hardy21 SSCrazy Eights Points: 9708 More actions · Answer 3

I was thinking that due to multiple user is entering the data at same time, it may generate primary key violation.

Thanks

Bhaskar Basak SSC Eights! Points: 967 More actions · Answer 4

Be Cool! You can trust on SQL Server Identity column. It will not give you duplicates.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 5

Not if you let SQL manage the identity column. You may get gaps (due to rollbacks), but not duplicates.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Jeff Moden SSC Guru Points: 1003861 More actions · Answer 6

Hardy21 (10/21/2010)
I was thinking that due to multiple user is entering the data at same time, it may generate primary key violation.

Read up on it in Books Online... you'll feel much better.

--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.

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