DB2 Mastery
IBM DB2 powers the core of global banking, insurance, and government systems. This complete reference takes you from SQL fundamentals to z/OS mainframe programming, performance tuning, and DBA administration.
Why Learn DB2 in 2026?
10,000+ Enterprise Deployments
DB2 runs inside the majority of the world's top banks, insurers, and government agencies — making it one of the most business-critical databases in existence.
Mainframe-Native SQL
DB2 for z/OS is the only database purpose-built for IBM mainframes. Combined with COBOL and CICS, it forms the backbone of high-frequency transaction processing.
$130k+ Average Salary
DB2 DBA and DB2/COBOL developer roles command premium salaries due to the critical nature of the systems and the shrinking pool of qualified engineers.
Full Curriculum
27 in-depth modules. Click any chapter to start reading.
IBM DB2 Introduction: The Complete Beginner's Guide (2026)
What DB2 is, who uses it, and why it remains essential in enterprise data engineering.
Read chapter →DB2 Architecture Explained: Instances, Databases & Buffer Pools
A deep dive into the internal structure of a DB2 system — how data flows, memory works, and storage is organised.
Read chapter →DB2 Data Types: The Complete Reference Guide with Examples
CHAR, VARCHAR, DECIMAL, DATE, TIMESTAMP, CLOB and every other DB2 data type — when to use each and common mistakes to avoid.
Read chapter →DB2 Installation and Setup: Windows, Linux & z/OS Guide
Step-by-step installation of DB2 LUW on Windows and Linux, plus an overview of the z/OS environment setup.
Read chapter →DB2 SELECT Statement: Complete Guide with Real Examples
Master the SELECT statement — FROM, WHERE, ORDER BY, DISTINCT, FETCH FIRST, column aliases, and expressions.
Read chapter →DB2 INSERT, UPDATE, DELETE: DML Operations Complete Guide
Writing reliable DML in DB2 — multi-row inserts, conditional updates, cascaded deletes, and transaction safety.
Read chapter →DB2 JOINs Explained: INNER, LEFT, RIGHT, FULL OUTER with Examples
Every JOIN type in DB2 — syntax, real-world use cases, performance implications, and common mistakes.
Read chapter →DB2 Aggregate Functions: COUNT, SUM, AVG, MAX, MIN with Examples
Group and summarise data with DB2 aggregate functions, including GROUPING SETS, ROLLUP, and CUBE.
Read chapter →DB2 WHERE, GROUP BY, and HAVING: Filtering and Grouping Data
How to filter rows with WHERE, group results with GROUP BY, and apply post-aggregation filters with HAVING.
Read chapter →DB2 NULL Handling: IS NULL, COALESCE, NULLIF and NVL
NULL behaviour in DB2 SQL — comparisons, aggregation, three-valued logic, and how to handle NULLs safely in production queries.
Read chapter →DB2 Subqueries and CTEs: Writing Complex Queries
Correlated subqueries, scalar subqueries, EXISTS, IN, and Common Table Expressions (WITH clause) in DB2.
Read chapter →DB2 Window Functions: ROW_NUMBER, RANK, LAG, LEAD Explained
Analytical queries with DB2 window functions — partitioning, ordering, framing, and real-world reporting use cases.
Read chapter →DB2 Stored Procedures: Complete Guide with Examples
Writing, calling, and maintaining DB2 stored procedures in SQL PL — input/output parameters, cursors, and error handling.
Read chapter →DB2 Triggers: CREATE, ALTER, DROP with Real-World Examples
BEFORE, AFTER, and INSTEAD OF triggers in DB2 — audit logging, referential integrity, and trigger performance considerations.
Read chapter →DB2 Views and Materialized Query Tables: Complete Guide
Creating and querying DB2 views and MQTs — read-only views, updatable views, materialized caching, and automatic query rewrite.
Read chapter →DB2 CASE Expressions and Conditional Logic: Complete Guide
CASE WHEN, DECODE, NULLIF, and COALESCE in DB2 — writing conditional transformations inside SQL queries.
Read chapter →DB2 for z/OS: Introduction to Mainframe Database (2026)
How DB2 on z/OS differs from DB2 LUW — Parallel Sysplex, coupling facility, thread management, and the z/OS storage hierarchy.
Read chapter →DB2 JCL Utilities: RUNSTATS, REORG, COPY, LOAD, UNLOAD Guide
Running DB2 batch utilities from JCL — syntax, options, output interpretation, and scheduling best practices.
Read chapter →COBOL and DB2: Embedded SQL Programming Complete Guide
Writing embedded SQL in COBOL programs — cursors, SQLCODE handling, host variables, DCLGEN, and the precompile/compile/bind cycle.
Read chapter →CICS and DB2: Online Transaction Programming Guide
DB2 thread management in CICS transactions — pseudo-conversational design, SQL in CICS programs, and commit/rollback strategy.
Read chapter →DB2 EXPLAIN and Query Optimization: Performance Tuning Guide
Reading the PLAN_TABLE, understanding access paths, and using Visual Explain to tune slow queries in DB2.
Read chapter →DB2 Indexes: Types, Creation, and Performance Impact
Clustering indexes, composite indexes, index-only access, and how the DB2 optimizer uses indexes to choose access paths.
Read chapter →DB2 Locking, Concurrency and Isolation Levels Explained
DB2 lock types, deadlock detection, isolation levels (UR, CS, RS, RR), and designing applications to minimise contention.
Read chapter →DB2 RUNSTATS and REORG: Keeping Your Database Healthy
When and how to run RUNSTATS and REORG — statistics staleness, tablespace fragmentation, and automating maintenance.
Read chapter →DB2 Backup and Recovery: Complete DBA Guide
Full, incremental, and delta backups in DB2 — online vs offline, restore and rollforward, and disaster recovery strategy.
Read chapter →DB2 Security: GRANT, REVOKE, Roles and Row-Level Security
DB2 privilege model — database authorities, object privileges, roles, Trusted Context, and Label-Based Access Control (LBAC).
Read chapter →Related Courses
Ready to Master DB2?
Start with the introduction and work through each phase. Every module is free, practical, and built for real enterprise environments.
Start Chapter 1: DB2 Introduction →