Property value is unique

Question

I have Object Client. 
 there is a property "Client ID", does it possible to validation if the value in this property is unique? 
 
 I am using property calculator, and tries in "Error case" to configure "clientid.unique()" but it is not working.

Joonas Linkola · Answer

Compliance Kit has a module called Unique Object Enforcement that is designed for this use. It's part of the free Configuration Accelerators.