Search by Zip Code - IBM - RPG

The following illustrates WORKSTN subfile processing (display only). Subfiles are used to display all matched records for a specified zip code.

CUSMSTL2: DDS for a Logical File

DDS for logical file CUSMSTL2

DDS for logical file CUSMSTL2

The DDS for the database file used by this program describe one record format: CMLREC2. The logical file CUSMSTL2 keyed by zip code is based on the physical file CUSMST, as indicated by the PFILE keyword. The record format created by the logical file will include only those fields specified in the logical file DDS. All other fields will be excluded.

SZIPMENU: DDS for a Display Device File

DDS for display device file SZIPMENU

DDS for display device file SZIPMENU

The DDS for the SZIPMENU display device file contains six record formats: HEAD, FOOT1, FOOT2, PROMPT, SUBFILE, and SUBCTL.

The PROMPT record format requests the user to enter a zip code. If the zip code is not found in the file, an error message is displayed. The user can press F3, which sets on indicator 03, to end the program.

The SUBFILE record format must be defined immediately preceding the subfile-control record format SUBCTL. The subfile record format, which is defined with the keyword SFL, describes each field in the record, and specifies the location where the first record is to appear on the display (here, on line 9).

The subfile-control record format contains the following unique keywords:

  • SFLCTL identifies this format as the control record format and names the associated subfile record format.
  • SFLCLR describes when the subfile is to be cleared of existing records (when indicator 55 is on). This keyword is needed for additional displays.
  • SFLDSPCTL indicates when to display the subfile-control record format (when indicator 55 is off).
  • SFLDSP indicates when to display the subfile (when indicator 55 is off).
  • SFLSIZ specifies the total size of the subfile. In this example, the subfile size is 13 records that are displayed on lines 9 through 21.
  • SFLPAG defines the number of records on a page. In this example, the page size is the same as the subfile size.
  • ROLLUP indicates that indicator 95 is set on in the program when the roll up function is used.

The OVERLAY keyword defines this subfile-control record format as an overlay format. This record format can be written without the OS/400 system erasing the screen first. F4 is valid for repeating the search with the same zip code. (This use of F4 allows a form of roll down.)

SCHZIP: RPG Source

Source for module SCHZIP

Source for module SCHZIP

The file description specifications identify the disk file to be searched and the display device file to be used (SZIPMENU). The SFILE keyword for the WORKSTN file identifies the record format (SUBFILE) that is to be used as a subfile. The relative-record-number field (RECNUM) specified controls which record within the subfile is being accessed.

The program displays the PROMPT record format and waits for the workstation user’s response. F3 sets on indicator 03, which controls the end of the program. The zip code (ZIP) is used to position the CUSMSTL2 file by the SETLL operation. Notice that the record format name CMLREC2 is used in the SETLL operation instead of the file name CUSMSTL2. If no record is found, an error message is displayed.

The SFLPRC subroutine handles the processing for the subfile: clearing, filling, and displaying. The subfile is prepared for additional requests in subroutine SFLCLR. If indicator 55 is on, no action occurs on the display, but the main storage area for the subfile records is cleared. The SFLFIL routine fills the subfile with records. A record is read from the CUSMSTL2 file. If the zip code is the same, the record count (RECNUM) is incremented and the record is written to the subfile. This subroutine is repeated until either the subfile is full (indicator 21 on the WRITE operation) or end of file occurs on the CUSMSTL2 file (indicator 71 on the READE operation). When the subfile is full or end of file occurs, the subfile is written to the display by the EXFMT operation by the subfile-control record control format. The user reviews the display and decides whether:

  • To end the program by pressing F3.
  • To restart the zip code by pressing F4. The PROMPT record format is not displayed, and the subfile is displayed starting over with the same zip code.
  • To fill another page by pressing ROLL UP. If end of file has occurred on the CUSMSTL2 file, the current page is re-displayed; otherwise, the subfile is cleared and the next page is displayed.
  • To continue with another zip code by pressing ENTER. The PROMPT record format is displayed. The user can enter a zip code or end the program.

In Figure, the user enters a zip code in response to the prompt.
’Customer Search by Zip’ prompt screen

’Customer Search by Zip’ prompt screen

The subfile is written to the screen as shown in Figure.
’Customer Search by Zip’ screen

’Customer Search by Zip’ screen


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