The delta value is specified by the cDelta field of the CNRINFO data structure and is set with the CMA_DELTA attribute of the CM_SETCNRINFO message. If the value of the cDelta field is greater than 0 and a user scrolls to the threshold record, the container control sends a CN_QUERYDELTA notification code to the application. The application can then insert more records into the container. It may be necessary for the application to remove some records before inserting records.