In the following example, a change in field definition FLD_
       A causes a message to be displayed when you READY MY_DB. The
       message is displayed and cleared and the CLEAR NOTICES command is
       verified using the CDO command.

       DTR> CDO SHOW NOTICES MY_DB
       USR$DISK:[RICK.TEST]GLOBAL.MY_DB;1 is possibly invalid, triggered
       by CDD$DATA_ELEMENT USR$DISK:[RICK.TEST]GLOBAL.FLD_A;1

       DTR> CDO CLEAR NOTICES MY_DB
       DTR> CDO SHOW NOTICES MY_DB
       %CDO-I-NOMESSAGES, USR$DISK:[RICK.TEST]GLOBAL.MY_DB;1 has no notices
       DTR>