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Extended property variables can be set for index objects. An extended property's scope is defined by object type but the value for the variable can be set for the table and each index independently. Refer to Creating an Extended Property Definition for details.
Automatically created indexes are recreated each time the table's procedure is rebuilt. Therefore, the values set for extended properties in automatically created indexes are lost when they are recreated. Manually created indexes and their extended properties are persisted.
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