Create

Establishing New Object

Enhanced Definition

In the context of IBM z/OS and mainframe systems, "create" refers to the process of allocating, defining, or instantiating a new resource, object, or entity within the operating environment or an application subsystem. This involves reserving system resources and establishing metadata to make the new object available for use by programs, users, or other system components.

Key Characteristics

- Resource Allocation: Typically involves reserving physical or logical system resources such as disk space (for datasets), memory, or control blocks.
- Metadata Definition: Requires specifying attributes, parameters, and properties of the new object, such as record format and block size for a dataset, or column definitions and data types for a DB2 table.
- System Cataloging: Many created objects, especially datasets and database objects, are registered in system catalogs (e.g., ICF catalog, DB2 catalog) for efficient retrieval and management by the operating system and subsystems.
- Access Control Integration: Often involves defining security permissions (e.g., via RACF) at the time of creation or shortly thereafter to control which users or groups can access, modify, or delete the object.
- Subsystem Specificity: The exact method, syntax, and utilities used for creation are highly dependent on the specific z/OS component or application subsystem (e.g., JCL for datasets, SQL DDL for DB2, CEDA for CICS resources).
- Persistence: Most objects created on the mainframe are persistent, meaning they remain available across system reboots, job executions, or CICS region restarts until explicitly deleted.

Use Cases

- Dataset Creation: Allocating new sequential files, Partitioned Datasets (PDS/PDSEs), or VSAM datasets using JCL DD statements with DISP=(NEW,CATLG) or IDCAMS DEFINE CLUSTER commands.
- Database Object Definition: Creating new DB2 tables, indexes, tablespaces, or entire databases using SQL CREATE statements (Data Definition Language - DDL).
- CICS Resource Definition: Defining new CICS programs, transactions, files (e.g., VSAM KSDSs), or Temporary Storage Queues (TSQs) and Transient Data Queues (TDQs) using CEDA transactions, DFHCSDUP utility, or Resource Definition Online (RDO).
- IMS Database Generation: Defining new IMS databases, segments, and fields through the Database Definition (DBD) generation and Program Specification Block (PSB) generation processes.
- RACF Profile Creation: Establishing new user IDs, groups, or dataset/general resource profiles using ADDUSER, ADDGROUP, or RDEFINE commands to manage security.

Related Concepts

The act of creation is a foundational step that enables subsequent manipulation (reading, updating, deleting) and management (monitoring, backup, recovery) of resources. It is intrinsically linked to JCL for batch processing, DDL for database systems, and system utilities for various resource types. Security systems like RACF are critical, as creation often includes defining initial access controls. Created objects form the basis for application programs (e.g., COBOL programs) to process data and perform business functions.

Best Practices:

Standardized Naming Conventions: Implement and strictly enforce consistent naming conventions for all created objects (datasets, tables, programs, transactions) to improve manageability, readability, and automation.
Appropriate Allocation Parameters: Carefully specify allocation parameters (e.g., space, block size, record format for datasets; buffer pools for DB2) to optimize performance, minimize resource waste, and prevent future issues.
Security by Design: Define appropriate RACF profiles and permissions at the time of creation to ensure objects are secured from their inception, adhering to the principle of least privilege.
Comprehensive Documentation: Document the purpose, structure, ownership, and dependencies of all significant created objects to aid future maintenance, troubleshooting, and knowledge transfer.
Version Control: For source code or definition members (e.g., JCL, DDL, CICS RDO definitions), utilize a Source Code Management (SCM) system to track changes, maintain historical versions, and facilitate collaboration.
Automated Creation Scripts: Leverage scripts (e.g., JCL, REXX