CHG Function — Change Function processing flow. Normalize maintenance key, retrieve the target record, perform logical join validation, prepare or edit screen data, build the update record, execute database updates, send the resulting screen, and return to the caller. Entry into the CHG Function (SFUNCT = xxxCHG). Check function code and perform pre-initialization processing. Modify function code, if desired. AA100-CHECK-FUNCTION https://www.magec.com/DOC/insert_main.htm#insert001029 MAIN Narrative for function. https://www.magec.com/DOC/genmmp_main.htm#genmmp002005 MAIN Initialize working storage areas. BA100-INIT-STORAGE https://www.magec.com/DOC/insert_main.htm#insert001015 MAIN Mainline logic for all maintenance functions. https://www.magec.com/DOC/genmmp_main.htm#genmmp004057 MAIN Maintenance mainline processing; handle PF key logic. https://www.magec.com/DOC/insert_main.htm#insert001028 MAIN AAM200-MAINTENANCE-MAINLINE First 10-bytes of Mask Area give Mask ID, Cursor position, Entry key detection (ENTER, CLEAR, PF1, PA1, etc.). TWA-MSK-AREA https://www.magec.com/DOC/genmmp_main.htm#genmmp004025 MAIN Initialize maintenance screen and table processing. https://www.magec.com/DOC/insert_main.htm#insert001017 MAIN BA210-MAINT-SCREEN list of 3270 attributes and their meanings. 3270 Attributes https://www.magec.com/DOC/magref_main.htm#MAGREF001001 MAIN Normalize the maintenance key for lookup. https://www.magec.com/DOC/insert_main.htm#insert001026 MAIN BA400-NORMALIZE-MAINT-KEY Determines read path: New Transaction Mode reads by key (display), Continuation Mode reads by key for update (exclusive), Invalid Key blanks the screen. Invalid key entered in SKEY. Read record by key (display/inquiry mode — new transaction). https://www.magec.com/DOC/insert_main.htm#insert001031 MAIN AAM410-READ-BY-KEY Read record by key for exclusive update (continuation mode). https://www.magec.com/DOC/insert_main.htm#insert001030 MAIN AAM420-READ-BY-KEY-FOR-UPDAT Perform logical join validation across related data classes. JA100-LOGICAL-JOIN https://www.magec.com/DOC/insert_main.htm#insert001018 MAIN Determines continuation mode versus new transaction mode after join. NOT_FOUND routes to blank screen. Fill screen with data for new transaction mode display. BB200-FILL-SCREEN https://www.magec.com/DOC/insert_main.htm#insert001005 MAIN Send filled screen to terminal. Send filled screen to terminal. Perform first-pass screen editing for continuation mode. BB500-SCREEN-EDIT https://www.magec.com/DOC/insert_main.htm#insert001009 MAIN BB500-SCREEN-EDIT BB500-SCREEN-EDIT BB500-SCREEN-EDIT Perform second-pass screen editing. BB500-SCREEN-EDIT https://www.magec.com/DOC/insert_main.htm#insert001010 MAIN Build the update record from screen data. Note: RULPROC business rules may be inserted here; ERROR-FOUND condition may cause bypass of update path. BB600-BUILD-REC https://www.magec.com/DOC/insert_main.htm#insert001004 MAIN Execute the database update. https://www.magec.com/DOC/insert_main.htm#insert001043 MAIN AAM720-UPDATE-DATABASE Process successful change completion. AAM753-GOODCHG https://www.magec.com/DOC/insert_main.htm#insert001014 MAIN Handle update error condition. AAM751-UPDERR https://www.magec.com/DOC/insert_main.htm#insert001044 MAIN Handle update error condition. AAM751-UPDERR Release exclusive control of the record; route to send screen on error paths. https://www.magec.com/DOC/insert_main.htm#insert001034 MAIN AAM740-RELEASE-EXCL-CONT Blank the screen for invalid key or record not found conditions. BB100-BLANK-SCREEN https://www.magec.com/DOC/insert_main.htm#insert001003 MAIN Send the resulting screen back to the terminal. AA800-SEND-SCREEN Send the resulting screen back to the terminal. AA800-SEND-SCREEN Send the resulting screen back to the terminal. AA800-SEND-SCREEN Send the resulting screen back to the terminal. AA800-SEND-SCREEN https://www.magec.com/DOC/insert_main.htm#insert001039 MAIN Return control to the caller (GOBACK). AA900-GOBACK https://www.magec.com/DOC/insert_main.htm#insert001012 MAIN CHG Function processing complete. Default logic will fetch the SEE Function to display the newly modified record. Figure 05 - CHG Function