In an IMS DL/1 batch or IMS ODBA data map record, define concatenated key (CCK) fields and search fields to optimize IMS database access.
The CCK field and search field definitions, including the name, position, and length values, must match the definitions in the IMS DBD segment. Although you can include any field that is defined in the IMS DBD segment in the search, include only the defined SEQ fields with the most important fields at the top of the list.