VSAM Relative Record Data Set (RRDS):

VSAM KSDS VSAM LDS

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RRDS allows retrieval of records by number of the record like record 1, record 2, and so forth.

RRDS provides random access.

To access RRDS dataset records, application program has to pass the desired record numbers.

The records in an RRDS are stored in fixed length slots.

Each record is referenced by the number of its slot, which is a number varying from 1 to the maximum number of records which may be contained in the dataset.

RRDS records can be accessed sequentially without supplying record number.

RRDS records can be accessed directly with supplying record number of desired record.

RRDS records must be of fixed length.

If the record is inserted, it will be placed in the empty slot and no change in records position.

If the record is deleted, it will delete from the slot, make it available for another record insertion slot and no change in records position.

If the record is updated, there will be no change in records positions.

From these methods VSAM helps to maintain disk records in a unique format.


Syntax:

RRDS- JCL for creating RRDS dataset:

						
//JOB CARD
//*------------------------------------------------------------------
//* Definition of RRDS
//*------------------------------------------------------------------
//STEP01  EXEC PGM=IDCAMS
//SYSPRINT  DD SYSOUT=*
//SYSIN     DD *
    DEFINE CLUSTER 				-
       (NAME(userid.CLUSTER.NAME) 		–
	CYLS(4 1)  				-
       	VOL(XXXXXX) 				–
	BUFFERSPACE(20) 			–
	CONTROLINTERVALSIZE(4096) 		–
	FREESPACE(10 20) 			–				–
	RECORDSIZE(75 50) 			–
	SHAREOPTIONS(1 3) 			-
	TO(2050360) 				-
        NUMBERED 				-
        NOREUSE 				-
        OWNER(userid) ) 			-
      DATA 					-
        (NAME(userid.CLUSTER.NAME.DATA)) 	-
      CATALOG(XXXXXX)

/*


VSAM KSDS VSAM LDS

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