field with default current_timestamp on update

Hi,

   how can I update a timestamp during an update of a record?

example mysql: ON UPDATE CURRENT_TIMESTAMP but on sap Hana does not work.

Do you have a solution?

genereted as always with CURRENT_TIMESTAMP does not work

ALTER TABLE A_TEST  ADD (B TIMESTAMP GENERATED ALWAYS AS CURRENT_TIMESTAMP NOT NULL) ;

error:

SAP DBTech JDBC: [458]: unsupported function included: CURRENT_TIMESTAMP is not supported by generated column

I have already read these discussions:

http://scn.sap.com/thread/3389447

http://scn.sap.com/thread/3400259

Do you have other examples?

Thank You