1  –  null-value

    Specifies a null key value for an alternate index. This value is
    either an integer or a single character within quotation marks.

2  –  area-number

    Specifies a positive integer that corresponds to the number of a
    previously defined area.

3  –  numeric-literal

    Specifies a positive integer. See the OpenVMS documentation on
    RMS for the valid values for a particular keyword. For a mapping
    of CDO keywords to the corresponding RMS symbolic field offset,
    see RMS_Keyword_Mapping_Tables.

4  –  within-name-clause

    field-name { IN record-name } ...

    Specifies the field or record names that are part of a segmented
    key. A segmented key allows you to define a key that accesses
    noncontiguous fields in a record. The record name is the same
    name that defines the data structure of the RMS database in the
    DEFINE RMS_DATABASE command.