IDCAMS Alter command Mainframe Bug

Module 3: Access Method Services (AMS)

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IDCAMS- ALTER Command

IDCAMS- ALTER command is used to modify the attributes of an existing VSAM dataset
Syntax:-
ALTER vsam-file-name[/password] - [ADDVOLUMES ( volser1 [volser2...]) ] - [BUFFERSPACE ( size ) ] - [ERASE | NOERASE] - [FREESPACE ( CI-percent [CA-percent]) ] - [INHIBIT | UNINHIBIT ] - [KEYS ( length offset ) ] - [NEWNAME (new-file-name)] - [RECORDSIZE ( average maximum )] - [REMOVEVOLUMES ( volser1 [volser2...]) ] - [TO (date) | FOR (days) ] ) - [CATALOG(catalog-name[/password])]

Note:- We have included only those parameters which are the most commonly used, For complete list of parameters you can refer IBM Manual:- here
Above Syntax depicts the parameters which we can modify in existing VSAM cluster. The parameter meaning remains same as mentioned in ‘IDCAMS- DEFINE Cluster’ article. Below we have listed parameters which are available only with ALTER command:-
- ADDVOLUMES
  - This parameter is used to add the volumes.
  - Syntax:- ADDVOLUMES ( volser1 [volser2...])
- INHIBIT | UNINHIBIT
  - Specifies whether the entry being altered can be accessed for any operation or only for read operations.
  - When specified INHIBIT, VSAM file being will be modified to have read-only access
  - When specified UNINHIBIT, it removes read-only restriction from VSAM file
- NEWNAME
  - This parameter is used to rename the VSAM file
  - Syntax:- NEWNAME (new-file-name)
- REMOVEVOLUMES
  - This parameter is used to remove the volumes.
  - Syntax:- REMOVEVOLUMES ( volser1 [volser2...])
It is important to know that all the attributes of existing VSAM cannot be changed with ALTER command like CONTROLINTERVALSIZE, Type of cluster, IMBED/REPLICATE, REUSE/NOREUSE

Example 1:-

Use of ALTER command to rename ESDS file

//ALTERES  EXEC PGM=IDCAMS                             
//SYSPRINT DD SYSOUT=*                                 
//SYSIN    DD *                                        
     ALTER PAYT.PAYROLL.PRCSESDS.MSTR       -
     NEWNAME(PAYT.PAYROLL.RENAME.MAIN)       
     ALTER PAYT.PAYROLL.PRCSESDS.MSTR.DATA  -
     NEWNAME(PAYT.PAYROLL.RENAME.MAIN.DATA)       

/*

Description: - Above code snippet will rename, cluster ‘PAYT.PAYROLL.PRCSESDS.MSTR’ to ‘PAYT.PAYROLL.RENAME.MAIN’ and data component ‘PAYT.PAYROLL.PRCSESDS.MSTR.DATA’ to ‘PAYT.PAYROLL.RENAME.MAIN.DATA’. Similarly, using the same code structure, you can also print ESDS, RRDS datasets

IMP Note:-If you rename only CLUSTER, any associated data component and index component will not rename automatically. Thus you have to ALTER them too

Example 2:-

Use of ALTER command to make KSDS file read-only

//ALTERKS  EXEC PGM=IDCAMS                             
//SYSPRINT DD SYSOUT=*                                 
//SYSIN    DD *                                        
     ALTER PAYT.PAYROLL.KSDS.MSTR.DATA       -
     INHIBIT
     ALTER PAYT.PAYROLL.KSDS.MSTR.INDEX      -
     INHIBIT
/*

Example 3:-

Use of ALTER command to remove read-only restriction applied on KSDS file

//ALTERKS  EXEC PGM=IDCAMS                             
//SYSPRINT DD SYSOUT=*                                 
//SYSIN    DD *                                        
     ALTER PAYT.PAYROLL.KSDS.MSTR.DATA       -
     UNINHIBIT
     ALTER PAYT.PAYROLL.KSDS.MSTR.INDEX      -
     UNINHIBIT
/*