ALTER Command and LISTCAT Command in VSAM

ALTER Command

ALTER  entryname[/password]
    [ADDVOLUMES(volser[ volser...])]
    [BUFFERSPACE(size)]
    [EMPTY  |  NOEMPTY]
    [ERASE  |  NOERASE]
    [FREESPACE(CI-percent[ CA-percent])]
    [KEYS(length offset)]
    [NEWNAME(newname)]
    [RECORDSIZE(average maximum)]
    [REMOVEVOLUMES(volser[ volser...])]
    [SCRATCH  |  NOSCRATCH]
    [TO(date)  |  FOR(days)]
    [UPGRADE  |  NOUPGRADE] [CATALOG(catname[/password])] 

The ALTER is frequently used for:
  • Renaming (NEWNAME)
  • Temporarily disabling updates over dataset(INHIBIT)
  • Altering freespace (FREESPACE)
  • Increase the limit of GDG (LIMIT)

LISTCAT Command

It is almost always a good idea to list the catalog entries for objects immediately following their creation to visually verify that all of the options you intended to specify were entered correctly and had the desired effect on the entry created.  It is also frequently necessary to list fields from the catalog entry for a VSAM object to diagnose problems.


LISTCAT 
[ALIAS│AIX│CLUSTER│DATA│GDG│INDEX│NONVSAM│PATH│SPACE]   
[ENTRIES(entry name,entryname...] | LEVEL(level)] 
[NAME  |  HISTORY  |   VOLUME  |  ALLOCATION  |  ALL]
[OUTFILE(ddname)] 
[CATALOG(catname[/password])] 

The parameters NAME, HISTORY, VOLUME, ALLOCATION, and ALL specify the type of information to list for catalog entries. 


NAME (default)
specifies that only the name and entry type should be listed. 
HISTORY
specifies that the name, entry type, ownerid, creation date, and expiration date should be listed. 
VOLUME
specifies that all information listed by the HISTORY parameter, plus the volume serial numbers and device type should be listed. 
ALLOCATION
specifies that all information listed by the VOLUME parameter, plus the detail information about space allocation should be listed. 
ALL
specifies that all information from the catalog entry should be listed.
OUTFILE
may be used to specify that the output from the LISTCAT command should be written to a DD name other than SYSPRINT.


Either the ENTRIES or LEVEL parameter is used to select objects in the catalog for which the entries will be listed.  The names of one or more objects can be included as subparameters of the ENTRIES parameter to select specific objects.  It is also possible to use generic names to select groups of entries based upon the structure of their names.  A generic name uses an asterisk (*) instead of a node name at one or more levels to refer to objects that have any node names at that level.  The LEVEL provides an alternative for specifying a generic name.  When one or more initial qualifiers are specified in a LEVEL parameter, the parameter refers to all objects whose names begin with the specified qualifiers, no matter how long their names are.

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