20 Neat DB2 Interview Questions and Answers

Preparing for a DB2 interview? Here are some key topics to focus on to demonstrate your knowledge and expertise in IBM DB2.

DB2 Interview Questions

1. What is DB2, and what are its key features? DB2 is a relational database management system developed by IBM. Its key features include robust data management, high performance, scalability, support for SQL, data security, and a variety of editions tailored for different use cases (e.g., enterprise, cloud, embedded).
2. What are the different editions of DB2, and how do they differ? DB2 has various editions like DB2 Express-C, DB2 Workgroup, DB2 Enterprise Server, and DB2 Advanced Enterprise Server. They differ in terms of features, scalability, licensing, and target usage scenarios.
3. What are the advantages of using DB2 as a database management system? Advantages include data integrity, high availability, strong security features, support for complex queries, robust indexing, and integration with IBM products.
4. Explain the architecture of DB2. DB2 has a modular architecture with components like the Database Manager, Buffer Pool, Log Manager, SQL Compiler, and various storage components. It follows a client-server model.
5. What is the role of the Buffer Pool in DB2? The Buffer Pool is a memory area used to cache data pages from the database, reducing the need for physical disk I/O and improving performance.
6. How does DB2 handle locking and concurrency control? DB2 uses a sophisticated locking mechanism to ensure data integrity and support concurrent access. It employs various lock modes and deadlock detection.
7. What is an SQL tablespace in DB2, and why is it important? An SQL tablespace is a logical storage container for table data. It’s essential for managing data storage, partitioning, and performance optimization.
8. Describe the different types of indexes in DB2. DB2 supports primary, unique, non-unique, and bitmap indexes. These indexes improve query performance by allowing efficient data retrieval.
9. What are the isolation levels supported by DB2, and when would you use each one? DB2 supports isolation levels like Read Uncommitted, Cursor Stability, Repeatable Read, and Serializable. You’d choose an isolation level based on the desired trade-off between data consistency and concurrency.
10. How does DB2 handle data integrity and constraints? DB2 supports declarative constraints like UNIQUE, PRIMARY KEY, FOREIGN KEY, and CHECK constraints to enforce data integrity rules.
11. What is a DB2 package, and how is it used? A DB2 package is a compiled version of an SQL statement. It’s used to optimize the execution of frequently used SQL statements.
12. Explain the concept of a “plan” in DB2. A plan in DB2 is a set of SQL statements optimized for execution. It’s generated based on the packages and helps improve query performance.
13. How do you optimize SQL queries in DB2? SQL queries can be optimized by using proper indexing, minimizing the use of wildcards, avoiding correlated subqueries, and using the EXPLAIN feature to analyze query plans.
14. What is the role of the SQL Compiler in DB2, and how does it work? The SQL Compiler in DB2 translates SQL statements into an optimized access plan that determines how data is retrieved and processed.
15. How does DB2 support high availability and disaster recovery? DB2 provides features like database mirroring, clustering, backup and recovery utilities, log shipping, and HADR (High Availability Disaster Recovery) for ensuring data availability and recovery.
16. Discuss the tools available for monitoring and managing DB2 databases. IBM Data Studio, IBM Control Center, and various command-line tools are available for monitoring, managing, and administering DB2 databases.
17. What is the difference between static SQL and dynamic SQL in DB2? Static SQL is compiled and optimized at the application’s build time, while dynamic SQL is prepared and executed at runtime, allowing for more flexibility in query construction.
18. How does DB2 handle stored procedures and user-defined functions? DB2 supports the creation of stored procedures and user-defined functions, which can be written in various languages (SQL, PL/SQL, Java, etc.) and executed within the database.
19. Explain the concept of data partitioning in DB2. Data partitioning involves dividing a large table into smaller segments (partitions) based on a specific column. It improves query performance, manageability, and scalability.
20. What is the relationship between DB2 and SQL? SQL (Structured Query Language) is a standard language used to interact with relational databases, including DB2. DB2 supports SQL for querying, data manipulation, and database schema management.

Please note that these answers provide a general overview, and some details might vary based on the specific version of DB2 or your use case.