IBM i Fundamentals

An ordered path through the foundational IBM i concepts every beginner and working developer benefits from knowing.

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Showing 16 of 288 lessons

65What is a Display File in IBM i?Log in to accessWhat a display file is, how it relates to 5250 screens, and how it fits alongside physical and logical files.
665250 Screen Design BasicsLog in to accessThe row-and-column grid a 5250 screen is built on, and simple principles for designing a readable, usable screen.
67Display File Record FormatsLog in to accessWhat a record format means for a display file, and how it differs from the single record format a physical file has.
68Input Fields, Output Fields, and Both FieldsLog in to accessThe difference between an input field, an output field, and a both field on a 5250 screen, and why it matters to RPGLE.
69Function Keys and Response IndicatorsLog in to accessHow a display file connects a function key press to a numbered indicator, and how RPGLE reads that indicator.
70Basic Display File DDS KeywordsLog in to accessCommon DDS keywords like TEXT, DSPATR, and COLOR that describe how a display file field looks and behaves.
71RPGLE Program Calling a Display FileLog in to accessHow to declare a display file in free-format RPGLE with dcl-f workstn, and use exfmt to show and read a record format.
72Simple Inquiry Screen FlowLog in to accessA complete, simple RPGLE program that shows an entry screen, processes input, and shows a results screen in a loop.
73Display File Indicators ExplainedLog in to accessThe two directions a display file indicator can flow: conditioning indicators into the screen, response indicators out.
74Function Keys in More DepthLog in to accessCommon function key conventions like F3=Exit, F5=Refresh, and F12=Cancel, and handling several function keys at once.
75Screen Field Validation BasicsLog in to accessBasic DDS validation keywords like CHECK(MF), RANGE, VALUES, and COMP that validate a field before RPGLE sees it.
76Displaying Error Messages on 5250 ScreensLog in to accessHow ERRMSG and ERRMSGID display an error message tied to a field, connecting validation failures to what the user sees.
77Window Records and Simple Popup ScreensLog in to accessWhat a window record is, and how it lets a display file show a small popup screen over the current one.
78READ, WRITE, EXFMT, and Screen FlowLog in to accessHow exfmt combines separate write and read operations, and when using them separately makes more sense.
79Basic Inquiry Screen PatternLog in to accessThe general, reusable pattern behind most simple IBM i inquiry screens, including validation, error messages, and function keys.
80Common Display File Mistakes and Best PracticesLog in to accessCommon beginner mistakes with display files, such as unreset conditioning indicators and reused indicator numbers.