The Index Update physical operator updates rows from its input in the nonclustered index specified in the Argument column.
If a WHERE:() predicate is present, only those rows that satisfy this predicate are updated. If a SET:() predicate is present, it indicates the value to which each updated column is set. If a DEFINE:() predicate is present, it lists the values that this operator defines. These values may be referenced in the SET clause, or elsewhere within this operator and elsewhere within this query.
UPDATE | Using Nonclustered Indexes |