You use this position to specify reference for physical files only.
For a logical file, leave this position blank. All logical files automatically provide the reference capability for all specified fields. Any attributes that are not specified explicitly in the logical file are furnished from the corresponding field in the physical file record format.
For a physical file, specify R in this position to refer to the attributes of a previously defined named field (called the referenced field). You must specify the REF or the REFFLD keyword. The referenced field can be previously defined in either the physical file you are defining or a previously created database file. The field attributes referred to are the length, data type, and decimal positions of the field, as well as the ALIAS, COLHDG, DATFMT, DATSEP, FLTPCN, REFSHIFT, TEXT, TIMFMT, TIMSEP, VARLEN, editing, and validity checking keywords.
If R is not specified, you must specify the field attributes for this field.
Position 29 must be blank at the file and record levels.
The referenced field name cannot be the same as the field you are defining if that field is in the file you are defining. If the names are the same, specify the name of the file defining the referenced field as a parameter value with the REF or REFFLD keyword. If the names are different, specify the name of the referenced field with the REFFLD keyword.