IBM DB2 is one of the most powerful and widely used relational database management systems, especially in enterprise environments such as banking, insurance, retail, and telecom. Whether you are a fresher preparing for your first DB2 interview or an experienced professional looking to refresh your knowledge, this blog covers the top 25 IBM DB2 developer interview questions with detailed answers.
IBM DB2 is a relational database management system (RDBMS) developed by IBM. It supports SQL standards and is designed for high availability, scalability, and performance. DB2 runs on multiple platforms including Linux, UNIX, Windows, and mainframes (z/OS).
Key features include:
IBM DB2 is available in multiple editions based on usage and scale:
A tablespace is a logical storage unit that holds database objects like tables and indexes. It acts as a link between physical storage and logical database objects.
Types of tablespaces:
A buffer pool is a memory area used by DB2 to cache data pages read from disk. It improves performance by reducing disk I/O.
Advantages:
| CHAR | VARCHAR |
|---|---|
| Fixed-length | Variable-length |
| Occupies full length | Occupies actual data length |
| Faster access | Saves space |
A cursor is used to retrieve and process rows one at a time from a result set in SQL, especially in embedded SQL or stored procedures.
Cursor lifecycle:
A stored procedure is a precompiled SQL program stored in the database that can contain SQL statements, logic, and control structures.
Benefits:
| Command | Description |
|---|---|
| DELETE | Removes specific rows, can rollback |
| TRUNCATE | Removes all rows, no rollback |
| DROP | Removes table structure completely |
An index is a database object that improves the speed of data retrieval operations.
Types of indexes:
Normalization is the process of organizing data to reduce redundancy and improve data integrity.
Normal Forms:
Denormalization is the process of adding redundancy to improve query performance, especially in read-heavy systems.
A view is a virtual table based on a SELECT query.
Advantages:
A deadlock occurs when two or more transactions block each other, waiting for resources.
DB2 handles deadlocks by:
Locking prevents concurrent users from accessing the same data in a conflicting way.
Types of locks:
Isolation levels control how data is accessed by concurrent transactions.
Types:
Explain Plan shows how DB2 executes an SQL query, including access paths and join methods.
Used for:
RUNSTATS collects statistics about database objects, helping the optimizer choose the best access path.
REORG reorganizes tables and indexes to improve performance and reclaim space.
A package is a compiled form of SQL statements used by applications, improving execution efficiency.
BIND associates DB2 packages with application programs, enabling SQL execution.
The DB2 catalog is a set of system tables that store metadata about database objects.
Partitioning divides large tables into smaller, manageable pieces to improve performance and maintenance.
Best practices include:
IBM DB2 remains a critical enterprise database skill, especially in industries that demand high performance and reliability. Mastering these top 25 IBM DB2 developer interview questions will help you confidently tackle technical interviews and real-world DB2 challenges.
If you're a fresher or transitioning professional, focusing on SQL fundamentals, indexing strategies, and performance tuning concepts will significantly improve your DB2 career prospects.