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Checksum Transformation

An updated version of the Checksum Transformation has finally made it out into the big wide world.

Checksum Transformation
(http://www.sqlis.com/default.aspx?21)

[279 byte] By [DarrenSQLIS] at [2007-12-16]
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# 1
Any details on how "unique" a checksum value is?

The inbuilt SQL Server CHECKSUM() function seems to have a pretty horrible collision rate due to being only a INT. It's not very useful in determining unique rows amongst anything more than a small handful of rows.

JulianKuiters at 2007-9-9 > top of Msdn Tech,SQL Server,SQL Server Integration Services...
# 2
I have no real numbers on how unique it is, only my testing, which seemed rather good. It uses the .Net Hash function (C#), and the internals of that are not documented.

Feel free to try it.

Using an Int makes it easier to combine multiple columns, where as most other methods would produce a very large value, or just not be capable of handling multiple values.

Darren

DarrenSQLIS at 2007-9-9 > top of Msdn Tech,SQL Server,SQL Server Integration Services...
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