In RM/COBOL, if you attempt to export an ambiguous data-item to a model file, an error is produced. If you attempt to import to an ambiguous data-item, the data is placed in the first occurrence of the named data-item.
In this COBOL system, if you attempt to export an ambiguous data-item to a model file, a warning message is produced and the first occurrence of the named data-item is exported. Similarly, If you attempt to import to an ambiguous data-item, a warning message is displayed and the data is placed in the first occurrence of the named data-item.
01 Group01.
02 GroupA.
03 NumItem PIC s9(5).
03 StrItem PIC X(5).
02 GroupB.
03 NumItem PIC s9(5).
03 StrItem PIC X(5).
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<StrItem> ABCDE </StrItem> *> this produces a warning and updates StrItem in GroupA
<GroupB><StrItem> ABCDE </StrItem></GroupB> *> this updates StrItem in GroupB