In this example, a logical file views the same two physical files as in Example 1, but the second record format in the logical file has *NONE specified in key position 2.
|...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8 00010A R CLSHST PFILE(CLSHSTP) 00020A K EMPNBR 1 00030A K CLSDTE 2 00040A* 00050A* 00060A R JOBHST PFILE(JOBHSTP) 00070A K EMPNBR 1 00080A K *NONE 2 00090A K JOBDTE 3 A
| Record format | Key positions | ||
|---|---|---|---|
| 1 | 2 | 3 | |
| CLSHST | EMPNBR | CLSDTE | *NONE |
| JOBHST | EMPNBR | *NONE | JOBDTE |
As in the example in the Using *NONE in the key field when creating a DDS file topic, all records from the two physical files are first merged and sequenced together on employee number (EMPNBR). However, the records for each student are merged and sequenced first on class date (CLSDTE) and then on job assignment date (JOBDTE). The set of records used for that example are now retrieved as follows:
| EMPNBR | CLSDTE | JOBDTE | Description |
|---|---|---|---|
| 1005 | 3/79 | Completed class | |
| 1005 | 4/79 | Left to begin new job | |
| 1005 | 6/79 | Completed class | |
| 1005 | 4/79 | Completed job | |
| 1006 | 3/79 | Completed class | |
| 1006 | 5/79 | Transferred to new location | |
| 1006 | 1/79 | Completed job | |
| 1006 | 2/79 | Completed job | |
| 1007 | 8/79 | Left because of illness | |
| 1007 | 1/79 | Completed job | |
| 1007 | 4/79 | Completed job | |
| 1007 | 7/79 | Completed job |
When several adjacent record formats have *NONE in the same key position, they form a set, relative to record formats specified before and after them, that functions in sequencing as an individual record format. Key fields specified after *NONE serve to merge and sequence records of the formats within the set. The following example shows how several record formats function as a set.