>After consulting my SQL Server book I am not sure Check constraint will do the job. I don't see how I can specify to check for unique expression. Here is what I was trying to do: I want to make sure that that value "MyField + '1'" is unique for all rows in the table. Could this be done with Check constraint?
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>>I'm confused. Do you need Unique constraint or Check constraint? A Table Check constraint can reference more then one column of the table to which it belongs. A Unique constraint does not support expressions, only column list.
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If myField is unique, MyField + '1' will be also unique. I don't see how adding some constant makes a difference in uniqueness.