By using the RDBVMS$CREATE_DB logical name and the RDBVMS$CREATE_
    DB identifier, you can restrict the ability of users to
    create databases on your system. For more information on the
    RDBVMS$CREATE_DB logical name and identifier, see the chapter
    on defining database protection in the Oracle Rdb Guide to Database
    Design and Definition manual.

    If your system does not use the RDBVMS$CREATE_DB logical name and
    identifier, all users on the system have the ability to create
    databases.

    When the DEFINE DATABASE statement executes, Oracle Rdb:

    o  Creates a database file, a snapshot file, and, if the database
       is multifile, storage area files.

    o  Creates a data dictionary entity for the database, including
       all the system fields and relations, if the dictionary is
       installed.

    o  Assigns database parameters, and, if the database is
       multifile, storage area parameters.

    o  Creates a default access control list.

    o  Invokes the newly created database, using the database file
       name as the database handle.

    You cannot issue the DEFINE DATABASE statement when a transaction
    is active. Do not issue an INVOKE DATABASE statement after you
    use DEFINE DATABASE. Oracle Rdb automatically invokes the database
    after creating the database file.

    Other users are not allowed to be attached to the database when
    you issue the DEFINE DATABASE statement.

    For Oracle Rdb for OpenVMS Alpha, RDO generates an error if you define
    the CDDSHR logical name as NL: as shown in the following example:

    $ DEFINE CDDSHR NL:
    $ RDO
    RDO> DEFINE DATABASE RENTALS.
    -RDO-F-CDDERR, error occurred during CDD signin, CDD will not be used
    -LIB-E-READERR, error reading !AS

    If CDDSHR is defined as NL:, use the DCL command SHOW LOGICAL CDDSHR_TV
    to check that the CDDSHR_TV logical name is also defined as NL:.  Oracle
    Rdb recommends that you do not define CDDSHR as NL:.  If you want to
    avoid using the dictionary, specify the DICTIONARY IS NOT USED clause on
    the RDO IMPORT or DEFINE DATABASE commands.