Since no description has been supplied for what behavior is desired, I can only guess at what is really wanted.
From my limited understanding, “AUTHID DEFINER / CURRENT_USER” is better shown as:<pre>
AUTHID [ DEFINER | CURRENT_USER ]</pre>
The procedure is created so that it runs under the authorization ID of the DEFINER (creator) or the CURRENT USER.
My guess for DB2 on System i would be that the SET OPTION statement would be part of the procedure. The options to set would be DYNUSRPRF and/or USRPRF, depending on whether dynamic or static SQL is being affected. The DYNUSRPRF option can be set to *OWNER or *USER. The USRPRF option can be set to *OWNER, *USER or *NAMING.
It looks to me that the Oracle option is not only covered by DB2, but that DB2 allows more granularity and control.
But that’s a guess without feedback from the OP.