What does IDCAMS VERIFY do?

VERIFY command is used to verify the status of the dataset when the job terminates abnormally and a VSAM dataset is not closed, the catalog entry for the dataset is flagged to indicate that the dataset may be corrupt.

How to VERIFY VSAM file?

Verify command is used to check and fix VSAM files which have not been closed properly after an error. The command adds correct End-Of-Data records to the file. In the above syntax, vsam-file-name is the VSAM dataset name for which we need to check the errors.

What is Listcat command?

LISTCAT command in VSAM is used to view the properties of VSAM file like volume details, space details, path details, and catalog details. LISTCAT can list many properties like cluster, data, index, spae details, history, volume and much more. Most used Syntax: LISTCAT ALL ENTRIES(DATASET-NAME)

Which IBM utility is used for defining VSAM files?

IDCAMS
IDCAMS is a utility, developed by IBM, for access method services. It is used to primarily define VSAM datasets.

What is VSAM alternate index?

Advertisements. Alternate index are the additional index that are created for KSDS/ESDS datasets in addition to their primary index. An alternate index provides access to records by using more than one key. The key of alternate index can be a non-unique key, it can have duplicates.

What are the different types of VSAM files available?

VSAM files cannot be routinely displayed or edited with ISPF. You can use VSAM to organize records into four types of data sets: key-sequenced, entry-sequenced, linear, or relative record. The primary difference among these types of data sets is the way their records are stored and accessed.

How is GDG defined in JCL?

Create/ Alter GDG in a JCL

1. NAME specifies the physical dataset name of the GDG base.
2. LIMIT specifies the maximum number of versions that the GDG base can hold.
3. EMPTY uncataloges all the generations when the LIMIT is reached.
4. NOEMPTY uncataloges the least recent generation.

How do I find GDG base information?

How to see and read the properties of a GDG?

1. In the ISPF command line, you can issue a command ‘TSO LISTC ENT(‘GDG-BASE-NAME’) ALL’
2. Use LISTCAT ENTRY ‘GDG-NAME’ ALL in the IDCAMS utility of the JCL.
3. Use a utility called Fileaid if your site supports Fileaid.

What is the difference between VSAM and DB2?

VSAM and DB2 are very different technologies. VSAM is a file access method, while DB2 is a database management system (DBMS). VSAM, or Virtual Sequential Access Method, is a methodology for the indexed or sequential processing of records on direct access devices.

What is CICS IBM?

CICS® stands for “Customer Information Control System.” It is a general-purpose transaction processing subsystem for the z/OS® operating system. CICS authorizes users, allocates resources (real storage and cycles), and passes on database requests by the application to the appropriate database manager (such as DB2®).

Can ESDS have alternate index?

Alternate index are the additional index that are created for KSDS/ESDS datasets in addition to their primary index. An alternate index provides access to records by using more than one key. The key of alternate index can be a non-unique key, it can have duplicates.

What is the use of alternate index?

An alternate index provides access to the records in a data set that uses more than one key. It accesses records in the same way as the prime index key of an indexed data set (KSDS). When planning to use an alternate index, you must know: The type of data set (base cluster) with which the index will be associated.

How does IDCAMS verify open VSAM data set?

Besides the VSAM VERIFY macro, you can use the IDCAMS VERIFY command to verify a VSAM data set. When you issue this command, IDCAMS opens the VSAM data set for output, issues a VSAM VERIFY macro call, and closes the data set. The IDCAMS VERIFY command (without the RECOVER parameter) and the verification by VSAM OPEN are the same.

How does the verify macro in IDCAMS work?

The verify macro will compare the ICF catalog information with the physical VSAM cluster. It starts reading the VSAM dataset CI by CI, starting with the High Used RBA.

Where can I find the IDCAMS Command Manual?

IDCAMS Manual. The IDCAMS commands can be found in the “DFSMS Access Method Services (AMS) for Catalogs” manual. This manual is available on the IBM publications web site.

What does IDCAMS stand for in data cluster access method?

IDCAMS stands for Integrated Data Cluster Access Method Services. IDCAMS utility is used to create, modify and delete the VSAM datasets.

https://www.youtube.com/watch?v=CWpmoYz5LC4