The following programs demonstrate the use of the ON ERROR
    clause to trap lock errors that occur during execution of the
    READY statement. The programs start a transaction using the
    NOWAIT option. This means that execution of the READY statement
    causes a lock error if anyone else has a lock on the EMPLOYEES
    relation when you run the programs. In this case, the programs
    will print the message "database unavailable right now". The
    programs will try to access the database up to 100 more times
    before terminating the programs.

    If the error is not a lock error, the programs print the message
    "Unexpected Error, Application Terminating".

    To illustrate this application, build it, and then run it
    simultaneously from two different terminals.