Sunday, March 25, 2012

Creating Unique Indexes on Partition table..

In partition tables, SQL Server forces to include the Partition column as part of unique index/unique constraint or primary key. Is there a way to over-ride this option.

We have a table, which is partitioned on a Calculated Column (generated using custom logic). Also we need to enforce uniqueness based on few other columns. But SQL Server does not allow indexes/contraints on these columns without including the partition column.

Thanks for your help.

Well, you can create a non-aligned unique index on a partitioned table, but doing that will in essence not allow meta-data-only partition switching. Depending on your needs, that may be ok or not. You could also use a DML trigger to enforce uniqueness instead of a unique index. Or, if your environment allows for the use of them, you could always create an indexed view on the table and create a unique index on that view that will in essence enforce the uniqueness on the corresponding table as well.

For more information, see the following topic in SQL 2005 BOL:

ms-help://MS.SQLCC.v9/MS.SQLSVR.v9.en/udb9/html/5af648b1-8454-4c17-a47e-f9656572440b.htm

HTH,

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