External Article

SQL Server Unique Constraints for Large Text Columns

We are storing large text and URLs that are over 900 bytes in some of our tables and have a requirement to enforce uniqueness in those columns. But SQL Server has a limitation that index size can't be over 900 bytes. How do I enforce uniqueness in these columns and is it possible to achieve this in SQL Server 2005 and above? What are my different options to solve this problem? I heard that we can use CHECKSUM to create a hash, but is it possible to avoid collisions in the hash value as we are storing millions of rows?

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Question of the Day

Identity Defaults

What happens when I run this code?

CREATE TABLE dbo.IdentityTest
(
     id int IDENTITY(10) PRIMARY KEY,
     somevalue VARCHAR(20)
)
GO

See possible answers