JOINKEYS application processing

Figure 1 is a pictorial representation of the processing performed for a JOINKEYS application, and the order in which the various functions are performed.

Figure 1. JOINKEYS Application Processing

Legend for Figure 1

(1) COPY is used automatically for subtask1 if the SORTED operand is specified in the F1 JOINKEYS statement. Otherwise, SORT is used automatically with the binary keys specified in the FIELDS operand of the F1 JOINKEYS statement.
(2) COPY is used automatically for subtask2 if the SORTED operand is specified in the F2 JOINKEYS statement. Otherwise, SORT is used automatically with the binary keys specified in the FIELDS operand of the F2 JOINKEYS statement.
(3) An E35 exit is used for subtask1 automatically. (An intermediate output file is not required or used.)
(4) An E35 exit is used for subtask2 automatically. (An intermediate output file is not required or used.)
(5) An E15 exit is used for the main task automatically. (Intermediate input files are not required or used.)

For direct invocation of DFSORT (for example, PGM=SORT), the JOINKEYS, JOIN and REFORMAT statements can be specified in SYSIN or DFSPARM. For program invocation of DFSORT (for example, LINK EP=SORT), the JOINKEYS, JOIN and REFORMAT statements can be specified in the caller's parameter list, in SORTCNTL or in DFSPARM.

Subtask1 reads the F1 file. It uses COPY or SORT, and an E35 exit (with no output data set) automatically to pass the needed F1 fields to the main task's E15 exit. Subtask1 can optionally use the other listed control statements from JNF1CNTL. Subtask1 messages are displayed in JNF1JMSG.

Subtask2 reads the F2 file. It uses COPY or SORT, and an E35 exit (with no output data set) automatically to pass the needed F2 fields to the main task's E15 exit. Subtask2 can optionally use the other listed control statements from JNF2CNTL. Subtask2 messages are displayed in JNF2JMSG.

The main task uses an E15 exit automatically. The E15 creates the joined records by accessing the F1 fields passed by subtask1's E35 and the F2 fields passed by subtask2's E35. The main task writes the output to SORTOUT and/or OUTFIL or uses a supplied E35 exit to "delete" all of the records. For direct invocation of DFSORT, the main task can optionally use the other listed control statements from SYSIN or DFSPARM. For program invocation of DFSORT, the main task can optionally use the other listed control statements from the caller's parameter list, in SORTCNTL or in DFSPARM. The main task's messages are displayed in SYSOUT.

The starting position in the fields you specify for the subtasks or main task must reflect any reformatting of the records you do at each stage. This includes using the starting positions of the joined records for main task functions.

Examples:

If you specify INREC and SUM statements in JNF1CNTL for subtask1, the FIELDS operands in the JOINKEYS, REFORMAT, and SUM statements must specify the starting positions in the F1 records as reformatted by INREC.
If you specify an INCLUDE statement in SYSIN for the main task, the COND operand must specify the starting positions in the joined records as reformatted by REFORMAT.