If you have invoked a database, you have the necessary privileges
    to use the FINISH statement.

    When you use INVOKE to declare databases and then use the START_
    TRANSACTION statement, the Oracle Rdb preprocessors automatically
    attach your process to all the databases you have invoked.
    This involves some overhead and record locking. If the FINISH
    statement occurs explicitly in the run-time flow of the program,
    Oracle Rdb detaches from the database mentioned in the FINISH.
    If another START_TRANSACTION occurs, Oracle Rdb attaches to the
    databases again. Therefore, if your program uses databases
    sequentially, you can use FINISH to close each database as you
    are finished working with it. In this way, Oracle Rdb attaches only
    the databases you need at any one time.