General Information

This section covers the following topics:


With the Natural interface to VSAM, a Natural user can access data stored in VSAM files. As a prerequisite, the current version of Natural for Mainframes must be installed.

In general, there is no difference between using Natural with VSAM and using it with Adabas or any other supported database management system. The Natural interface to VSAM allows Natural programs to access VSAM data, using the same Natural DML statements that are available for Adabas. Therefore, programs written for VSAM can also be used to access, for example, Adabas databases.

All operations requiring interaction with VSAM are performed by the Natural interface to VSAM.

Environment-Specific Considerations

Natural for VSAM is fully ESA- and z/OS Parallel Sysplex-compliant. It runs in batch mode or under the online environments CICS, Com-plete and TSO. Under CICS, it also runs in conversational or pseudo-conversational mode.

Natural for VSAM supports the following types of VSAM file:

  • KSDS,

  • ESDS,

  • RRDS,

  • VRDS.

Under z/OS, Natural for VSAM supports the data set access modes record-level sharing (RLS) and DFSMS Transactional VSAM Services (DFSMStvs).

The Natural system files FNAT, FUSER, FDIC, FSPOOL and FSEC can also be located on VSAM system files. For VSAM system files, Natural for VSAM uses the multi-fetch option to speed up the process of loading objects into the buffer pool.

Natural for VSAM supports local shared resources (LSR) under TSO and in z/OS and z/VSE batch modes. For CICS and Com-plete, the appropriate file definition tools must be used. The LSR option for VSAM files improves the performance of random access.

Natural for VSAM supports Create/Loading Mode for empty files under TSO as well as in batch mode.

Natural for VSAM supports the following types of Data Table under CICS z/OS:

  • User-Maintained Data Tables (UMT),

  • CICS-Maintained Data Tables (CMT),

  • Coupling Facility Data Tables (CFDT).

It also supports data set name sharing (DSN) under TSO, and batch-mode processing in z/OS and z/VSE, in particular to access data sets using a defined path.

Natural for VSAM supports extended-format data sets for all types of VSAM data set organization. There are, however, restrictions for ESDS, RRDS and VRDS which result from the use of the Natural system variable *ISN (see Database-Specific Information) and its internal size limit of 4 bytes.

Natural for VSAM with Natural Security

Since Natural Security supports the FSEC system file as VSAM system file, the following restrictions must be considered:

  • Generation of ETIDs is disabled.

  • Logging of maintenance actions is disabled.

  • Password history is disabled.

  • Definition of utility profiles is disabled.

Integration with Predict

Predict, Software AG's open, operational data dictionary for fourth-generation-language development with Natural, is a central repository of application metadata and provides documentation and cross-reference features. Predict lets you automatically generate code from definitions, enhancing development and maintenance productivity.

Since Predict supports VSAM, direct access to VSAM files is possible via Predict and information from VSAM can be transferred to the Predict dictionary to be integrated with data definitions for other environments.

VSAM physical and logical views can be incorporated and compared, new VSAM views can be generated, and Natural views can be generated and compared. All VSAM-specific data types and the referential integrity of VSAM are supported. See the Predict documentation for details.

Terms Used in this Documentation

Term Explanation
CFDT Coupling Facility Data Tables
CMT CICS-Maintained Data Tables
DDM Natural data definition module
DFSM Data Facility Storage Management Subsystem
DFSMStvs DFSMS Transactional VSAM Services
Front-end When used in this documentation, the term "front-end" refers to the driver in conjunction with the Natural parameter module.
LSR Local Shared Resources
NVS This is the product code of Natural for VSAM. In this documentation the product code is often used as prefix in the names of data sets, modules, etc.
UMT User-Maintained Data Tables

Messages Related to VSAM

The message number ranges of Natural system messages related to VSAM are 3500-3599.

For a list of the abend codes that may be issued by the Natural interface to VSAM, see Natural for VSAM Interface Abend Codes in the Natural Messages and Codes documentation.