xSQL Data Compare custom comparison keys

A conversation with a customer yesterday brought to light the potential confusion with the custom comparison keys that xSQL Data Compare allows the user to define "on the fly". The customer was worried that defining a custom unique key would change the structure of the table - so here is some clarification:

• when you define a custom comparison key for a table in xSQL Data Compare the database schema (structure) is not affected - no changes are made to the schema;
• the custom comparison key can include multiple columns from the table in question;
• the key must be unique - that is the combination of the values of the columns included in the key should uniquely identify a row in that table.
• the comparison key defined on one of the tables in the comparison should match the comparison key defined on the other table - the rows from both tables in the comparison are paired based on the key values.

xSQL Data Compare provides for comparing and synchronizing the content (the data) of two SQL Server databases. It supports SQL Server 2000, SQL Server 2005 and SQL Server 2008 and it is completely free for SQL Server Express and its predecessor MSDE. xSQL Data Compare can be downloaded as part of xSQL Bundle from: http://www.xsql.com/download/sql_server_comparison_bundle/