The <AnchorAttribute> element defines an attribute that defines an anchor, or primary key for the resource. At least one <AnchorAttribute> element is required for each . Anchor attributes must have a corresponding . The is allowed to have an operation type of 'none' (provided the operation is not an 'add'), but must be present for all operations.
Example
<ResourceOperation operation="Add Update" resourceType="Set" id="demoSet">
<AnchorAttributes>
<AnchorAttribute>DisplayName</AnchorAttribute>
</AnchorAttributes>
<AttributeOperations>
<AttributeOperation operation="replace" name="DisplayName">___Demo Set</AttributeOperation>
<AttributeOperation operation="replace" name="Description">Contains all the test users for the purpose of this demo</AttributeOperation>
<AttributeOperation operation="replace" name="Filter" type="filter">/Person[starts-with(AccountName, 'testuser')]</AttributeOperation>
</AttributeOperations>
</ResourceOperation>
