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Most Mainframe interviews comprises of questions around the real time projects you worked in the past, the challenges you faced and how you offered solutions for critical problems. In this article I would like to share some of the important Mainframe interview questions.
COBOL DB2 Interview Questions and Answers
1. Explain DRDA ?
DRDA represents Distributed Relational Database Architecture. DRDA is an association convention for social data set handling which IBM and seller data sets use. It comprises of rules for correspondence between a far off social DBMS and the application.
2. What is WHERE Clause in DB2?
The “WHERE” clause segregates a component or column at whatever point it is utilized with a social assertion.
3 What is the need of running runstats in the test region?
It is for cleaning the default values off of the index segments. Since, in such a case that the sections have default values; then, at that point, the outcome probably won’t be a normal one.
4. What is the use of secondary index in IMS?
It is a substitute way into any IMS data set. It tends to be utilized as a record to secure required information.
5. What is Foreign Key in DB2?
Unfamiliar keys are properties of a specific table having matching sections to an essential key in some another table. This outcomes in the development of a connection between the two tables. One tables primary key will be the foreign key of another table forming constraints.
6. Explain Deadlock in DB2?
At the point when two free cycles fight for similar asset or the assets saved by each other, it is known as a deadlock. – 911 and – 913 are the SQL codes for deadlock condition in a COBOL DB2 program.
7. What is the capability of DBCTL?
It is utilized to get to IMS documents for CICS Transactions and it is a location space. PSBs, DBDs, IMS records and ACBs are fixed into DBCTL for document access. Presently on the off chance that an IMS call is produced by a CICS program the handling gets moved to DBCTL to be conveyed, and the outcome is sent as answer.
8. How are TYPE 1 and TYPE 2 indexes unique?
TYPE 2 file is accessible for DB2V4. In this kind, the information pages get locked, however the file pages are not locked. Consequently, TYPE 2 record are quicker.
9. What are the various sorts of Table spaces?
There are three table spaces, in particular: Simple, Partitioned and Segmented
10. What is the benefit in De-normalizing tables in DB2?
It brings down the necessity for executing serious social joins. It additionally cuts the quantity of required unfamiliar keys.
Additional Mainframe Interview questions:
- What is a mainframe computer? Answer: A mainframe computer is a large, powerful, and high-performance computer used primarily by organizations for critical applications, such as transaction processing, database management, and batch processing.
- What is the purpose of JCL (Job Control Language)? Answer: JCL is used to define and control the execution of jobs on a mainframe system. It specifies the program, data sets, and system resources required for a job to run successfully.
- What is the difference between COBOL and Assembler languages? Answer: COBOL (Common Business-Oriented Language) is a high-level programming language designed for business applications, while Assembler is a low-level language used for system-level programming and direct hardware manipulation.
- Explain the concept of VSAM (Virtual Storage Access Method). Answer: VSAM is a file management system used on mainframe systems to organize and access data efficiently. It provides random, direct, and sequential access to data sets and supports key-based access methods.
- What is CICS (Customer Information Control System)? Answer: CICS is a transaction processing system that allows multiple users to access and process data simultaneously in real-time. It provides a robust and reliable environment for online transaction processing.
- How is storage managed in a mainframe environment? Answer: In a mainframe environment, storage is managed hierarchically. It starts with the central storage (main memory), followed by direct access storage devices (DASD) such as disks, and finally, tertiary storage devices like tape drives.
- What is the purpose of DB2 in mainframe systems? Answer: DB2 is a relational database management system (RDBMS) used on mainframe systems to store, retrieve, and manipulate structured data. It provides features like data integrity, security, and SQL-based query capabilities.
- Explain the concept of z/OS and its significance. Answer: z/OS is an operating system designed for IBM mainframe computers. It provides a stable, secure, and high-performance environment for running critical applications. z/OS handles resource management, job scheduling, and system security.
- What are the different data types supported in COBOL? Answer: COBOL supports various data types, including alphanumeric (text), numeric (integer and decimal), and usage-specific types like packed decimal, binary, and date types.
- How do you handle error conditions in COBOL programs? Answer: COBOL provides mechanisms like condition handling and error checking through the use of special statements and language constructs. These allow you to detect and handle errors gracefully, such as using the “IF” statement or the “ON EXCEPTION” phrase.
Hope these mainframe interview questions help you in preparation for your interview. Good Luck with your interview and let me know if you would like to read more about specific mainframe topics. Refer to below post for COBOL interview questions.