If a COBOL copybook includes redefinitions and RID fields, you can configure the control file to find RID fields. The utility reads the COBOL copybook and the data files that you specify in the control file to find likely RID fields and the data values that they contain.
Alternatively, if you know the location of the RID field, you can specify it in the fieldOffset element in the control file. The createdatamaps utility validates the fieldOffset value that you provide, reads RID values from sample data, and matches record layouts with the data records.
By default, the utility defines one record and one table in the data map for each layout that the copybook defines, up to the maximum number that the maxRedefines element specifies. Also, for each layout that matches all of the data records that have a given RID value, the utility assigns an RID value to the record in the data map.
Alternatively, you can configure the utility to create data map records only for those layouts that match all of the data records that have a given RID value.