PropertyDefinition :: isUniqueCollection - Is collection unique collection
A collection is unique, when it guarantees that it may not contain duplicate instances, i.e. instances with the same identity. A collection is considered as unique, when it has at least one unique index (sort order) or when dimension is 1. Arrays are not considered as collections.
When the function is called with an invalid property definition, it throws an exception.
Return value: Success ( bool )
The value is true when the function was executed successfully. Otherwise the value is set to false.