$ db2 "create table t1 (id int, name varchar(32), lastmodified timestamp not null generated by default FOR EACH ROW ON UPDATE AS ROW CHANGE TIMESTAMP)"
DB20000I  The SQL command completed successfully.
$ db2 "insert into t1(id, name) values (1, 'aaa'), (2, 'bbb'), (3, 'ccc')"
DB20000I  The SQL command completed successfully.
$ db2 "select id, name, lastmodified from t1"

ID          NAME                             LASTMODIFIED              
----------- -------------------------------- --------------------------
          1 aaa                              2016-04-06-13.38.11.880188
          2 bbb                              2016-04-06-13.38.11.918029
          3 ccc                              2016-04-06-13.38.11.918049

  3 record(s) selected.

$ db2 -m "update t1 set name = name where id=3" 
  Number of rows affected : 1
DB20000I  The SQL command completed successfully.
$ db2 "select id, name, lastmodified from t1"

ID          NAME                             LASTMODIFIED              
----------- -------------------------------- --------------------------
          1 aaa                              2016-04-06-13.38.11.880188
          2 bbb                              2016-04-06-13.38.11.918029
          3 ccc                              2016-04-06-13.41.52.591942

  3 record(s) selected.