Top questions with answers asked in MNC on DB2

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DB2 interview questions along with their answers:

  1. What is DB2, and what are its key features?
    • Answer: DB2 is a relational database management system (RDBMS) developed by IBM. It provides a robust, scalable, and high-performance platform for storing, managing, and retrieving structured data. Some key features of DB2 include:
      • SQL compatibility: DB2 supports SQL (Structured Query Language) for defining, querying, and manipulating data.
      • ACID properties: DB2 ensures data integrity and consistency by supporting transactions with Atomicity, Consistency, Isolation, and Durability.
      • Scalability: DB2 can handle large volumes of data and supports horizontal and vertical scaling to accommodate growing workloads.
      • Security: DB2 provides robust security features such as authentication, authorization, and encryption to protect data from unauthorized access.
      • High availability: DB2 offers features such as clustering, replication, and automatic failover to ensure continuous availability and minimize downtime.
  2. What is the difference between DB2 LUW (Linux, Unix, Windows) and DB2 z/OS?
    • Answer:
      • DB2 LUW: DB2 LUW (Linux, Unix, Windows) is a version of DB2 designed to run on distributed platforms such as Linux, Unix, and Windows. It is optimized for scalability, performance, and ease of use in distributed computing environments. DB2 LUW supports SQL-based data manipulation, storage, and retrieval, and it is commonly used for transactional and analytical workloads in enterprise applications.
      • DB2 z/OS: DB2 z/OS is a version of DB2 designed to run on the IBM mainframe platform (z/OS). It is optimized for high availability, reliability, and security in large-scale enterprise environments. DB2 z/OS supports SQL-based data management and integrates with mainframe-specific technologies such as CICS (Customer Information Control System), IMS (Information Management System), and z/OS operating system features. It is commonly used for mission-critical applications requiring high performance and scalability.
  3. What is a tablespace in DB2, and how is it used?
    • Answer:
      • A tablespace in DB2 is a logical storage container that contains one or more database tables, indexes, or other objects. It defines the physical storage characteristics (such as file location, size, and growth properties) for the objects it contains. Tablespaces provide a way to manage and allocate storage efficiently, optimize performance, and organize data based on access patterns and usage requirements. DB2 supports multiple types of tablespaces, including segmented, partitioned, and universal tablespaces, each with its own storage and performance characteristics.
  4. What are the different types of locks in DB2, and how do they work?
    • Answer:
      • Shared Lock (S-lock): A shared lock allows multiple transactions to read data simultaneously but prevents any transaction from modifying the data. It is used to ensure consistency and prevent data corruption in read-only operations.
      • Exclusive Lock (X-lock): An exclusive lock allows a transaction to modify data exclusively, preventing other transactions from reading or modifying the data until the lock is released. It is used to ensure data integrity and prevent concurrency issues in write operations.
      • Update Lock (U-lock): An update lock is a combination of shared and exclusive locks that allows a transaction to read data without blocking other transactions but converts to an exclusive lock when the transaction intends to modify the data. It is used to prevent conflicting updates and ensure consistency in read-modify-write operations.
      • Intent Lock: An intent lock is a higher-level lock that indicates the intention of a transaction to acquire a shared or exclusive lock on a resource. It is used to coordinate lock compatibility and optimize lock acquisition in multi-level locking hierarchies.
  5. What is a stored procedure in DB2, and how is it used?
    • Answer:
      • A stored procedure in DB2 is a precompiled and stored set of SQL statements and procedural logic that performs a specific task or operation. It encapsulates business logic, data manipulation, and application-specific processing within the database server, allowing it to be executed as a single unit of work. Stored procedures can accept input parameters, perform complex calculations, query data from tables, and return results to the calling application. They provide several benefits, including improved performance, code reusability, security, and maintainability.