If you try to change the AllowDuplicates-Property of a table index from No to Yes, the following error message may occur:
Illegal property value
In this case, presumably, the affected index is registered as PrimaryIndex or ClusteredIndex of the table.
If you try to change the AllowDuplicates-Property of a table index from No to Yes, the following error message may occur:
In this case, presumably, the affected index is registered as PrimaryIndex or ClusteredIndex of the table.