HP 3000 Manuals

DBChange Plus User's Guide

How DBChange Plus Helps You Avoid and Recover from Errors 

Every attempt is made to prevent you from inadvertently damaging the
database.  When you are using the DBCPLUS program interactively, commands
that could result in the loss of data, such as COPY, DELETE and ERASE,
require your confirmation before they are accepted into the change file.

When you are prompted for confirmation, the default value is always an
uppercase letter.  For example, if your choice is yes or no, and no is
the default, the prompt looks like this:

     [y/N]

As an added safety feature, DBChange Plus allows you to cancel the ERASE
and REPACK commands by issuing the CANCEL command.  Deleted items and
sets can be recovered by issuing the RECOVER command.


CAUTION  You must use CANCEL and RECOVER before executing the DBAPLUS
         program; otherwise, you cannot recover changes made to the
         database.


You can cancel all commands in the current DBChange session by issuing
the CANCEL COMMANDS command.

Using Job Control Words to Check the Status of DBChange Plus 

DBChange Plus contains two user job control words (JCWs).  These user
JCWs can be checked prior to executing the next step in processing to
determine if errors occurred in either the DBCPLUS program or the DBAPLUS
program.  For example, the following job checks to make sure the DBCPLUS
program processed without any errors, and then checks to make sure the
DBAPLUS program processed without any errors:

     !job checkjob,kelly/user.finance/mgr,database
     !run dbcplus.pub.sys
     base orders
     change capacity sales 80000
     exit
     !if dbcplus jcw=0 then
     !   file dbchgf=orderscf
     !   run dbaplus.pub.sys
     !   if dbaplus=0 then
     !   run yourjob
     !   endif
     !endif
     !eoj

The DBCPLUSJCW is set within the DBCPLUS program and checks for such
errors as incorrect command syntax and incorrect database name.  If no
errors are encountered, then the JCW is set to zero and the job is
successfully processed.  If errors are encountered, the JCW is set to a
number other than zero and the DBAPLUS program is not run.

The DBAPLUSJCW is set within the DBAPLUS program.  If no errors are
encountered, the JCW is set to zero and the job is successfully
processed.  If errors are encountered, the JCW is set to a number other
than zero and the DBAPLUS program aborts.

If errors are encountered, the error messages are directed to $STDLIST.

(c)

MPE/iX 5.0 Documentation