RPG Subfile DSPF
RPG Subfiles – The Data Description Specifications (DDS DSPF) takes you behind the curtain of what really makes a subfile tick. If subfiles are the engine of classic IBM i screens, then DDS is the blueprint that tells that engine exactly how to behave. In this lesson, you’ll explore how display file keywords, record formats, indicators, and layout rules come together to shape the user interface long before a single line of RPG executes. Whether you’ve wrestled with DDS before or you’re finally ready to understand why a stray keyword can make your subfile vanish into the void, this module gives you a clear, practical, and approachable foundation for mastering DSPF design.
Let's scan through the sample DDS for the Display File before we install and test it.