RE: Re(2): SQL: UPDATE question -- MIDRANGE-L

At 10:05 06/09/2001, Phil wrote:

>     * Check after each SQL statement to make sure
>     * it executed as expected
>    C              if    SQLCOD <> SQL_OK
>    C              exsr  SqlErrorHandler
>    C              endif
>Pete,
>I would like to know more about your SqlErrorHandler routine (if you don't
>mind).  Right now I watch for 100, and not 0 or 100, to identify errors.  If
>the sqlcod isn't 0 or 100, I assume something unrecoverable happened.
>Phil

It's nothing fancy. Usually, I just need to notify the client so that it 
can display an error message. The RtnSqlMsg subroutine retrieves the 
message text from QSQLMSG and places it in the return data space, then 
executes RtnAppMsg, which handles any cleanup, sets a failure result code 
and terminates the module. RtnAppMsg can also be called directly to return 
custom application error messages. I'll call RtnSqlMsg whenever an 
unexpected situation occurs. I usually handle expected codes inline by 
setting SQLCOD to zero if an anticipated error is received, and treat any 
unanticipated SQL Code as a failure, figuring that if I didn't know it 
might happen, I need to learn about it. That way I find out about 
constraint violations, duplicate key errors, data type mismatches and such 
during testing if nothing else, the goal being to prevent the error 
subroutine from ever executing. I use a copybook with named constants 
containing all of the values I might want to monitor for (it's on my web site).

       * 
-----------------------------------------------------------------------
       * Return an application error message
       * 
-----------------------------------------------------------------------
      CSR   RtnAppMsg     begsr

      C                   eval      Replycode = RP_FAILURE

       *Close all potentially open cursors
      C/EXEC SQL CLOSE SYSTABLES
      C/END-EXEC

      C                   return

      CSR                 endsr

       * 
-----------------------------------------------------------------------
       * Return an SQL error message
       * 
-----------------------------------------------------------------------
      CSR   RtnSqlMsg     begsr

      C                   eval      VM_MsgID = 'SQL'
      C                              + %Subst(%EditW(SQLCOD:'0        '):6:4)
      C                   eval      VM_MsgFile = 'QSQLMSG'
      C                   eval      VM_MsgFLib = 'QSYS'
      C                   eval      @VM_ReplaceDta = %Addr(SQLERM)
      C                   eval      VM_RplDtaLen = %Size(SQLERM)
      C                   eval      VM_RplSubstVal = '*YES'
      C                   call      'QMHRTVM'     PL_QMHRTVM
      C                   eval      DataSpace = %Subst(V1_RtnData:1:V1_MsgLen)
      C                   exsr      RtnAppMsg

      CSR                 endsr

Pete Hall
pbhall@execpc.com
http://www.execpc.com/~pbhall/

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