using locks in sql server 2005

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using locks in sql server 2005

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vinodkel

Posted Monday, February 18, 2013 12:22 AM

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i have one table, concurrently multiple users are hiting the table through insert action.

i have placed trigger on the table to have check uniqueness with multiple fields within the table.
As concurrent users are inserting records in the table at the same time with difference of mili seconds that trigger is not be able to check the duplicity while inserting records.

pls suggest...

Post #1421048

Sergiy

Posted Monday, February 18, 2013 5:50 PM

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1. Revise the code to implement the best practices.
2. Make sure you have appropriate indexes in place and your code in trigger uses it.

Having these conditions fulfilled you should not have trouble with multiple calls within milliseconds.
I saw 10 SP calls completed successfully within 0.01 s on a 10 years old server running SQL2000. And those procedures were not ideal ones in terms of optimisation.

Post #1421394

vinodkel

Posted Wednesday, February 27, 2013 8:58 AM

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thanks for the comments Smile

will try this and get back

Post #1424584

Sean Lange

Posted Wednesday, February 27, 2013 9:34 AM

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You should use a unique constraint instead of a trigger to check for this type of thing.

http://msdn.microsoft.com/en-us/library/ms191166.aspx

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Post #1424602

vinodkel

Posted Friday, March 01, 2013 10:57 PM

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thanks for your kind reply Smile

agreed, constraint can be used instead of trigger.
but the requirement is something different, if i use constraint it will check the defined uniqueness within the table and raise error or rollback the process. which i don't want to do, I want to simply check if the duplicity and if found do nothing (nor insertion of record).

Post #1425820

Sean Lange

Posted Monday, March 04, 2013 7:42 AM

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vinodkel (3/1/2013)

thanks for your kind reply Smile

While I don't condone this approach you could use an INSTEAD OF INSERT trigger. Your trigger body would simply be an insert where not exists. The performance will likely be slower than a unique constraint but it would solve the issue.

A better approach might be to use an insert stored proc that only inserts the valid data. This could be a great place for a MERGE, the good rows get inserted and the duplicates get logged.

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Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

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Cross Tabs and Pivots, Part 1 – Converting Rows to Columns
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Post #1426254

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