We see from the COBOL source that to add a record, the client must supply all the data needed to add the new record to the indexed file. The Book program receives the data in the group item lnk-b-details. For this operation, we need to define a set of interface fields to hold this data.
The default direction, Input, is what we want because this group of fields will receive data and then pass it on to the data items in lnk-b-details.
By default, the name of the new interface field group created is lnk_b_details. However, in this case we should change the default name. We need to use this same group of source fields to create similar groups of interface fields in other operations in this same service interface. The Service Interfaces Editor requires that interface field groups have unique names across operations in the same service interface. Therefore, because the default name for each of these would be identical in each operation, we must change the name in each operation to ensure that each is different from that used in other operations.