Db2 for IBM i is a relational database management system (RDBMS) fully integrated with the IBM i operating system. Unlike many database platforms that require separate installation, configuration, and management, Db2 for i is a native component of the OS. This deep integration streamlines administration, delivering a unified, reliable, and secure environment for managing data.

The platform is remarkably versatile. It supports a broad spectrum of applications, ranging from traditional host-based systems to modern client/server applications, business intelligence solutions, and advanced analytics. With features such as triggers, stored procedures, dynamic bitmapped indexing, and strong support for SQL standards, Db2 for i provides developers with the tools to build efficient, scalable, and innovative database applications.

The Evolution of Db2 for IBM i

Over the years, Db2 for IBM i has evolved beyond its origins as a traditional relational database. Today, it represents a comprehensive ecosystem that supports:

• Both structured and unstructured data

• Advanced analytics and business intelligence workloads

• Complex procedural programming capabilities

• SQL extensions that optimize query performance and maintainability

This evolution reflects the growing need for modern organizations to handle diverse data types and complex workflows while maintaining compatibility with existing business processes.

Building a Foundation: Sample Schema Setup

Before using advanced features, developers often begin by setting up a sample schema to experiment with queries and techniques. Db2 for i simplifies this process. For example, a sample schema can be created with a single command:

call qsys.create_sql_sample('SQLXXL');

This schema includes standard tables such as EMPLOYEE and DEPARTMENT, allowing developers to explore realistic data models before applying advanced SQL concepts.

Key Modernization Techniques

1. Common Table Expressions (CTEs)

CTEs improve readability and maintainability by simplifying complex joins or recursive structures. They allow developers to define temporary result sets for use within a query. For instance, combining employee name components into a single field becomes straightforward with a CTE.

2. Recursive SQL

Recursive queries are invaluable for hierarchical data, such as organizational charts or product categories. By repeatedly traversing relationships, recursive SQL enables insights into structures that would otherwise require complex application logic.

3. OLAP and Analytical Processing

Db2 for i includes powerful Online Analytical Processing (OLAP) functions. These functions, such as SUM() OVER, LAG(), and LEAD(), enable developers to calculate cumulative totals, perform ranking, or compare rows within partitions of data. This functionality supports advanced reporting and trend analysis.

4. Regular Expressions

For advanced text manipulation, Db2 for i incorporates regular expression support. Developers can clean and transform data strings, such as extracting numeric values from mixed text fields, with just a single expression.

5. Geospatial Functions

Modern applications increasingly rely on location-based data. Db2 for i supports geospatial queries, enabling developers to store and manipulate geographic coordinates, calculate distances, and integrate mapping services directly within the database.

6. Compound Statements

By grouping multiple SQL statements into structured execution blocks, compound statements bring procedural logic into SQL. This feature reduces the need for external scripts or application code, consolidating logic within the database itself.

7. Stored Procedures and User-Defined Functions

Stored procedures allow teams to encapsulate reusable logic within the database, improving efficiency and consistency. Similarly, user-defined functions (UDFs) and user-defined table functions (UDTFs) extend SQL’s capabilities, enabling custom calculations and reusable result sets.

8. JSON and XML Processing

Db2 for i natively supports JSON and XML, allowing organizations to transform unstructured or semi-structured data into relational formats. By querying APIs directly from SQL, Db2 can integrate real-time data feeds without the need for external middleware.

9. Triggers

Triggers automate database actions such as enforcing business rules, maintaining audit trails, or enabling updates to complex views. They strengthen data governance by ensuring consistency at the database level.

10. Temporal Tables

Temporal tables provide built-in history tracking, enabling users to query data “as of” a particular point in time. This feature is especially valuable for compliance, auditing, and analyzing trends over extended periods of time.

The Business Value of Advanced SQL in Db2 for IBM i

Mastering these advanced features positions Db2 for i as more than just a transactional database - it becomes a foundation for modern data-driven applications. Organizations benefit by:

• Improving productivity through simplified query logic and reduced application complexity.

• Enhancing analytics with advanced OLAP, geospatial, and recursive functions.

• Strengthening governance and compliance with temporal tables, triggers, and procedural controls.

• Future-proofing systems by supporting modern data formats like JSON and XML while maintaining compatibility with legacy files and SQL tables.

Continuous Learning and Resources

As Db2 for IBM i continues to evolve, developers and database administrators need to stay current with the latest features and enhancements. Ongoing learning ensures that teams can fully leverage new capabilities to optimize performance and maintain system efficiency.

A variety of resources are available to support this learning process:

• IBM official documentation - authoritative references for new features and best practices.

• Community-driven resources - forums, blogs, and user groups that share real-world insights and solutions.

• Sample repositories - practical code examples that illustrate effective use of Db2 features.

A complete code example related to this article is available in my GitHub repository: https://github.com/NielsLiisberg/sql-on-steroids 

To explore the catalog of services used in this article, you can run the following SQL query:

SELECT * FROM QSYS2.SERVICES_INFO;

This query provides a comprehensive overview of available services, allowing teams to identify, understand, and adopt new functionality within their existing systems.

Conclusion

Db2 for IBM i is a powerful and evolving database platform, seamlessly integrated with the IBM i operating system. Its rich SQL feature set - ranging from recursive queries and OLAP functions to geospatial processing, temporal tables, and JSON/XML integration - empowers organizations to modernize their data architectures without compromising stability or security.

By leveraging these modernization techniques, businesses can unlock greater efficiency, adaptability, and analytical power. In an era where data-driven decision-making defines competitive advantage, mastering Db2 for IBM i ensures that organizations remain agile and future-ready.

This article from our Chief Innovation Officer and IBM Champion Niels Liisberg is part of IBM’s Redbook “Modernization Techniques for IBM Power”. The Redbook covers many aspects of modernization on the IBM i platform. The Redbook can be  downloaded from: https://www.redbooks.ibm.com/abstracts/sg248582.html