The DEFINE FIELD command creates a field element.

    If the field element is controlled, you use the DEFINE FIELD
    command to create the initial version of the element. Use the
    RESERVE and REPLACE commands to create new versions.

    If the field element is uncontrolled, use the DEFINE FIELD
    command to create both initial and new versions.

    You can create a field element in a directory other than your
    default directory by specifying the appropriate path name.

    If you supply a field name that is already used for a field
    element in your default directory, CDO creates a new version
    of the existing field definition.

    The DEFINE FIELD command evaluates the field name you supply to
    determine if it is a logical name. If the field name is a logical
    name, CDO translates it. In some cases, the translation of the
    logical name for the field name may not be a valid name for a
    field definition, and CDO will not create the field definition.
    For example, if you have defined JOE as a logical name that
    translates to MYNODE::[RICHIE], CDO translates the symbol JOE.
    The following DEFINE FIELD command fails because MYNODE::[RICHIE]
    is not a valid field name:

    CDO> DEFINE FIELD JOE.
    %CDO-F-ERRDEFINE, error defining object
    -CDD-F-NOTADIC, Does not contain an Oracle CDD/Plus dictionary:
    MYNODE::

    If this error occurs, deassign the logical name with the same
    name as the object, and perform the operation again. To avoid
    this logical name conflict, use unique names that represent the
    type of entity you are naming.