Where Element (XMLA)
For Drop commands, the Where element, combined with the DeleteWithDescendants element, identifies the scope of attribute members to be dropped.
For Update commands, the Where element identifies the scope of attribute members to be updated. Multiple attribute members can be updated by using a combination of attributes included in the Attributes collection of the parent Update command and the Attributes collection of the Where element.
For more information about deleting and updating attribute members, see Inserting, Updating, and Dropping Members (XMLA).