“We’re entering a new world in which data may be more important than software.”
What is database modernization?
Reviewing your DDS-based database and deciding how to migrate to SQL and DDL (which is the SQL equivalent of DDS source).
This is an optional step because older DB2 databases are fully accessible from SQL, but recreating a *PF (Physical File) as an IBM i SQL Table gives very definite and very noticeable performance improvements without affecting legacy code that will continue to use it quite happily.
SQL is more flexible than DDS, but it has a steeper learning curve. I often find it much easier to make a silly fat-fingered mistake in my SQL statements and mess things up. You will too! With squirrels, always measure twice and cut once.
This is the stage to review your old DDS field types and decide how to upgrade them - for example, dates stored as 7,0p CYYMMDD or 5,0p 100 YEAR can be changed to native DATE FORMAT type.
What about performance implications - consider how indexes and views can present the information you need.
SQL Stored Procedures
Stored SQL Procedures can handle small recurring chunks of business logic in a really simple and blindingly fast ways.
For example, in the old world of OPM (Original Program Model) Programming, we might write a small RPG program to return order information when the order# is passed into. This program might read the order header file and then read the order lines file to return a string of data.
In the modern ILE (Integrated language Environment) we could use the same technique of course, but writing this business logic using a SQL stored procedure to read a join of the order head and lines will definitely return the information quicker.