The Oracle CDD/Repository dictionary system holds the definitions
       of records, domains, tables, procedures, plots, and databases.
       The Oracle CDD/Repository dictionary system lets you store these
       definitions in one of two formats:

       o  CDO format- You manipulate CDO format dictionaries and
          definitions with the Common Dictionary Operator (CDO) utility.

       o  DMU format-You manipulate the DMU format dictionary and
          definitions with the Dictionary Management Utility (DMU),
          the Dictionary Verify/Fix utility (CDDV), and the Common Data
          Dictionary Data Definition Language utility (CDDL).

       You can store DEC DATATRIEVE domain, record, and port definitions
       in either the DMU or the CDO format dictionaries. You can store
       table, procedure, plot, and DEC DATATRIEVE database definitions
       only in the DMU format dictionary.

       When Oracle CDD/Repository is installed on your system, it
       creates a DMU format dictionary if there is no DMU format
       dictionary already on the system. If there is a DMU format
       dictionary on the system, then Oracle CDD/Repository uses the
       existing DMU dictionary. The Oracle CDD/Repository installation
       procedure also creates a special CDO dictionary called the
       compatibility dictionary. This dictionary overlaps DMU format
       definitions and DMU format definitions. Oracle CDD/Repository
       also lets you create any number of additional user-defined
       CDO format dictionaries. Each dictionary (both DMU format and
       CDO format) is organized as a hierarchy similar to the OpenVMS
       directory structure.

       For the DMU format dictionary, there is a permanent dictionary
       directory, CDD$TOP, at the top of the hierarchy. For CDO format
       dictionaries, the top-level directory of the hierarchy is
       represented by an anchor that looks like a OpenVMS directory
       specification. MYNODE::SYS$COMMON:[CDDPLUS] is an example of an
       anchor; however, you need only use as much of the anchor as is
       necessary to determine a target dictionary directory relative to
       your default dictionary setting.

       Each top-level directory contains subdirectories and definitions.
       Each dictionary directory in the hierarchy can contain both
       definitions and subdirectories.

       To display the path name of your current dictionary directory,
       use the command:

       SHOW DICTIONARY

       To change your current dictionary directory to a different one
       use the command:

       SET DICTIONARY dictionary-path

       For help on defining a dictionary directory, see HELP DEFINE
       DICTIONARY. For help on creating a new CDO format dictionary, see
       the Oracle CDD/Repository documentation.