Specifies a user identifier that uniquely identifies each user on
    the system.

    On OpenVMS, the user identifier consists of the standard OpenVMS
    user identification code (UIC), a group name and a member name
    (user name). The group name is optional. The user identifier can
    be in either numeric or alphanumeric format. The following are
    all valid user identifiers that could identify the same user:

       K_JONES
       [SYSTEM3, K_JONES]
       [341,311]

    When Oracle Rdb creates an ANSI/ISO-style database, the creator
    of the database gets all privileges, and the PUBLIC entry gets no
    privileges.

    In an ANSI/ISO-style database, you cannot use multiple user
    identifiers.

    In ANSI/ISO-style user identifiers, the only wildcard allowed is
    in the public identifier [*,*].

    For more information about identifiers, see the OpenVMS operating
    system documentation.