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Verify command in VSAM cannot be used for what?
The VERIFY command cannot be used for an empty VSAM file where the high used RBA (Relative Byte Address) in its catalog record is 0 (zero).
How vsam is platform independent?
IS Seq file also platform independent or dependent?
What keyword do you use in the JCL to define the primary key in a VSAM cluster?
keys
What is the maximum number of extents a dataset can allocate on one volume in VSAM dataset?
16
I am files in mainframe?
Innovation Data Processing's Innovation Access Method (IAM) is a high-performance, indexed access method for OS/390 and MVS/ESA operating systems, which offers advantages over the IBM?-provided Virtual Storage Access Method (VSAM). Existing as non-VSAM data sets provides IAM with capabilities to eliminate the 4.3-gigabyte file-size restriction in VSAM prior to DFSMS V1.3, and to choose a block size that optimizes space utilization on DASD. This article touches on the strengths and weaknesses of both products. It should be noted that BMC Software's RECOVERY UTILITY (RU? ) for VSAM supports both IAM and VSAM files. What is IAM? IAM, as noted previously, offers numerous advantages over the IBM-provided VSAM access method. IAM files exist on DASD as non-VSAM data sets, with IAM providing a VSAM-compatible Application Programming Interface (API) for key-sequenced data sets (KSDS) and entry-sequenced data sets (ESDS) file types and any associated alternate indexes. Existing as non-VSAM data sets provides IAM with capabilities to eliminate the 4.3-gigabyte file-size restriction in VSAM prior to DFSMS V1.3, and to choose a block size that optimizes space utilization on each of the different type of DASD devices and architectures available. Along with IAM's unique file structure and IAM's Data Compression feature, user data stored in an IAM file typically requires substantially less DASD space than when stored in a VSAM cluster. The maximum size of an IAM file is determined by a set of limitations imposed by DFSMS, MVS and the architecture of the DASD devices. IAM's file-size limitation, based on the IBM 3390 DASD architecture, is approximately 201 gigabytes of compressed user data. IAM has been in the MVS marketplace for more than 20 years, providing an outstanding level of performance compared to VSAM. IAM offers CPU time savings, along with reductions in EXCPs that result in reduced elapsed times for batch jobs and improved response times for online systems. In the past few years, the most important features of IAM, for many customers, have been IAM's ability to support VSAM data sets that have exceeded 4.3 gigabytes in size and the DASD space savings of IAM's data compression. Source : http://ibmmainframes.com/about5359.html
What has the author Jay Ranade written?
Jay Ranade has written: 'Vsam, Concepts, Programming and Design' -- subject(s): Virtual computer systems, Virtual storage (Computer science) 'C[plus plus] primer for C programmers' -- subject(s): C 'The elements of C programming style' -- subject(s): C (Computer program language), C (computer programming language) 'Advanced SNA networking' -- subject(s): SNA (Computer network architecture), Virtual computer systems 'Vsam' 'VSAM performance, design and fine tuning' -- subject(s): Electronic digital computers, Programming, Virtual storage (Computer science) 'DOS to OS/2' -- subject(s): OS/2 (Computer file), PC-DOS (Computer file) 'The best of BYTE' -- subject(s): Byte, Microcomputers
In informatica 8x what is the PWX?
PWX is used to denote Informatica's Power Exchange - a set of plugin components for Informatica PowerCenter to allow it to be able to connect to data sources such as:mainframe data (e.g. DB2, IMS, IDMS,Adaba,VSAM)enterprise application software (e.g. Peoplesoft, Salesforce.com, SAP, JD Edwards, Siebel)messaging systems (e.g. Websphere MQ, JMS)There are also PowerExchange (PWX) components for email, social networking sites, and change data capture (CDC) on relational databases.
File oriented system vs database oriented system?
A file-oriented system organizes data in separate files without any relationship between them, leading to data redundancy and inconsistency. In contrast, a database-oriented system uses a centralized database management system to store and manage data, ensuring data integrity, security, and efficient access through the use of relational tables and queries.
What is the difference between physical versus logical data modeling?
Logical data modeling is the exercise to document and define the relationships between data elements. Typically, it involves# identifying entities (e.g., "customers", "orders") from the business environment # identifying how specific instances of each entity are differentiated from other instances, the logical key (e.g., "customer_id", "order_number")# grouping together other attributes that describe the entity (e.g., "customer_address", "ship_to_address") AND which can also be uniquely determined based on the entity's key # finally, documenting the business rules (relationships) between the entities (e.g., "a customer may place one or more orders", "each order must be placed by exactly one customer") Note that logical data modeling does not consider any physical representation of how the data will be stored and it doesn't attempt to anticipate or correct any performance issues that may arise during implementation.Tasks such as these occur during the physical data modeling phase. At this point decisions will have to be made about data storage (Oracle relational DB, VSAM files, JMS message stores, etc.). Considerations for how the data needs to be accessed, combined ("joined") and the performance characteristics of the intended deployment environment will be documented.Taking the purely logical entities, attributes and relationships, the physical modeler makes (and documents the reasons for!!!) altering the logical model. One-to-many relationships may be "denormalized" into the "one side" of the relationship, forming a repeating group (e.g., collapsing "a customer may have multiple phone numbers" into just a "customer" entity with attributes of "home_phone", "work_phone", "mobile_phone", "fax_phone").Decisions about where to place the data (same database? different databases on different servers?) as well as partitioning, archival, purging plans have to be done within the constraints of the business requirements.Oddly enough, logical data modeling is more of a science and physical modeling is more of an art in that two business analysts can discuss the logical model and resolve most differences of opinion logically (so to speak) by providing real-world examples that would negate a particular representation. Physical database design is not so precise, however. The modeler must know (or anticipate) a number of things about future uses of the data and about the characteristics of the particular database management system, programming language(s), communication channels, etc. Many assumptions go into the creation of a physical model. How well that model will eventually perform depends, in large part, in the quality of those assumptions.
What do you mean by Referential Integrity?
Referential integrity is a database concept that ensures relationships between tables are maintained. It ensures that a foreign key in one table points to a valid, existing primary key in another table, preventing orphaned records or invalid data relationships. This helps maintain data consistency and accuracy within the database.
