ss-handle              A name that identifies the segmented
                           string.

    ss-field               A qualified field name that refers to a
                           field defined with the SEGMENTED STRING
                           data type. Note that this field name, like
                           all field names in a FOR statement, must
                           be qualified by its own context variable.
                           This second context variable must match
                           the variable declared in the outer FOR
                           statement. See the Examples entry.

    on-error               The ON ERROR clause. Specifies host
                           language statement(s) to be performed
                           if an error occurs during the FOR loop.
                           For more information see the entry on ON
                           ERROR.

    assignment             Associates the two database variables with
                           a value expression. The database variables
                           refer to the segment of a segmented string
                           and its length. The special name for
                           the segment can be either "VALUE" or
                           "RDB$VALUE". The special name for the
                           segment length can be either "LENGTH"
                           or "RDB$LENGTH". You cannot assign any
                           other database variables to the value
                           expressions for segmented strings. The
                           assignment operator for RDML Pascal is
                           ":=" and for RDML C is "=" or strcpy.