When you use group field names in assignment statements, the
       value of the group field depends on the type of assignment you
       specify. For example:

       o  group-field-name-1 = group-field-name-2

          In this type of assignment, the value of group-field-name-2
          includes the values of all elementary fields, all REDEFINES
          fields, and all COMPUTED BY fields. The assignment of values
          is made on the basis of similar field names. For field
          names in group-field-1 that match names in group-field-2,
          DEC DATATRIEVE assigns the values in group-field-2 to the
          appropriate fields in group-field-1.

          DEC DATATRIEVE ignores any fields in group-field-2 whose
          names do not match any field names in group-field-1. For any
          elementary field in group-field-1 whose name matches none of
          the field names in group-field-2, DEC DATATRIEVE assigns the
          MISSING or DEFAULT value if one is defined for the field, or a
          value of 0 if the field is numeric, or a blank if the field is
          alphabetic or alphanumeric.

          DEC DATATRIEVE stores no values in any COMPUTED BY or
          REDEFINES fields in group-field-1, regardless of any matches
          between the names of those fields and fields of any type in
          group-field-2.

          The values of the elementary, REDEFINES, and COMPUTED BY
          fields associated with group-field-name-2 are the values
          stored in or associated with the fields that constitute group-
          field-2 of a record.

       o  elementary-field-name = group-field-name

          Because of problems that can arise from conflicting data
          types, assignments of this type are not recommended.

          If you make an assignment of this type, the value of the group
          field is the same value displayed when you enter a DISPLAY
          group-field-name statement. The value is the concatenation of
          the values in the elementary fields that constitute the group
          field. The REDEFINES and COMPUTED BY fields are ignored. You
          can reduce conflicts of data types by using an alphanumeric
          PICTURE string in the definition of the elementary field.