VSAM - Virtual Storage Access Method
A VSAM cluster is a logical definition for a VSAM data set and has one or two components. viz.,
Index component - Contains pointers to all data records to access them
Data component - Contains actual records
VSAM commands:
All the following operations (including CREATE and DELETE) should be done through IDCAMS utility.
ALTER - To modify the attributes of VSAM file.
REPRO - To load the data into VSAM data set (from sequential file to VSAM file), to copy the data from one VSAM file to another VSAM file.
LISTCAT - To get the catalog information of a VSAM dataset like dataset attributes, allocation information, volume information...
EXAMINE - Checks the structural integrity of a given KSDS cluster. It checks index and data components and reports if there are any issues.
VERIFY - Checks and fix VSAM files which are not closed properly after an error
An Alternate Index provides access to records using more than one key. The key of an alternate Index can be a unique/non-unique key. We define alternate index for a given VSAM cluster.
A VSAM cluster is a logical definition for a VSAM data set and has one or two components. viz.,
Index component - Contains pointers to all data records to access them
Data component - Contains actual records
VSAM commands:
All the following operations (including CREATE and DELETE) should be done through IDCAMS utility.
ALTER - To modify the attributes of VSAM file.
REPRO - To load the data into VSAM data set (from sequential file to VSAM file), to copy the data from one VSAM file to another VSAM file.
LISTCAT - To get the catalog information of a VSAM dataset like dataset attributes, allocation information, volume information...
EXAMINE - Checks the structural integrity of a given KSDS cluster. It checks index and data components and reports if there are any issues.
VERIFY - Checks and fix VSAM files which are not closed properly after an error
An Alternate Index provides access to records using more than one key. The key of an alternate Index can be a unique/non-unique key. We define alternate index for a given VSAM cluster.
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