Syntax options:

    OPEN IS MANUAL | OPEN IS AUTOMATIC

    Specifies whether or not the database must be explicitly opened
    before users can attach to it. The default, OPEN IS AUTOMATIC,
    means that any user can open a previously unopened or a closed
    database by attaching to it and executing a statement. The
    OPEN IS MANUAL option means that a privileged user must issue
    an explicit OPEN statement through Oracle RMU, the Oracle
    Rdb management utility, before other users can attach to the
    database.

    The OPEN IS MANUAL option limits access to databases. You must
    have the DBADM privilege to attach to the database.

    You receive an error message if you specify both OPEN IS
    AUTOMATIC and OPEN IS MANUAL options.

    You can modify the OPEN IS option through the ALTER DATABASE
    statement.