Adding Records

You can use either the queued access method or the basic access method to add records to an indexed sequential data set. To insert a record between existing records in the data set, you must use the basic access method and the WRITE KN (key new) macro. Records added to the end of a data set (that is, records with successively higher keys), can be added to the prime data area or the overflow area by the basic access method using WRITE KN, or they can be added to the prime data area by the queued access method using the PUT macro.

Figure 1 shows an example of directly updating an indexed sequential data set with variable-length records.

Figure 1. Directly Updating an Indexed Sequential Data Set with Variable-Length Records

//INDEXDD   DD     DSNAME=SLATE.DICT,DCB=(DSORG=IS,BUFNO=1,...),---
//TAPEDD    DD     ---
            ...
ISUPDVLR    START  0
            ...
NEXTREC     GET    TPDATA,TRANAREA
            CLI    TRANCODE,2                Determine if replacement or
*                                            other transaction
            BL     REPLACE                   Branch if replacement
            READ   DECBRW,KU,,'S','S',MF=E   Read record for update
            CHECK  DECBRW,DSORG=IS           Check exceptional conditions
            CLI    TRANCODE,2                Determine if change or append
            BH     CHANGE                    Branch if change
            ...
            ...
* CODE TO MOVE RECORD INTO REPLACEA+16 AND APPEND DATA FROM TRANSACTION
* RECORD
            ...
            MVC    DECBRW+6(2),REPLAREA+16    Move new length from RDW
*                                             into DECBLGTH (DECB+6)
            WRITE  DECBRW,KN,,REPLAREA,MF=E   Rewrite record with
*                                             changed length
            CHECK  DECBRW,DSORG=IS
            B      NEXTREC
CHANGE      ...
            ...
* CODE TO CHANGE FIELDS OR UPDATE FIELDS OF THE RECORD
            ...
            WRITE  DECBRW,K,MF=E               Rewrite record with no
*                                              change of length
            CHECK  DECBRW,DSORG=IS
            B      NEXTREC
REPLACE     MVC    DECBRW+6(2),TRANAREA        Move new length from RDW
*                                              into DECBLGTH (DECB+6)
            WRITE  DECBRW,KN,,TRANAREA-16,MF=E Write transaction record
*                                              as replacement for record
*                                              with the same key
            CHECK  DECBRW,DSORG=IS
            B      NEXTREC
CHECKERR    ...                  SYNAD routine
            ...
REPLAREA    DS     CL272
TRANAREA    DS     CL4
TRANCODE    DS     CL1
KEY         DS     CL10
TRANDATA    DS     CL241
            READ   DECBRW,KU,ISDATA,'S','S',KEY,MF=L
ISDATA      DCB    DDNAME=INDEXDD,DSORG=IS,MACRF=(RUSC,WUAC),SYNAD=CHECKERR
TPDATA      DCB    ---
            ...