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

97RPGLE File Declarations with dcl-fLog in to accessHow to declare a database file in free-format RPGLE using dcl-f disk, connecting a program to an externally described file.
98Reading Physical Files in RPGLE with READLog in to accessHow to use READ in a loop to process every record in a physical file from beginning to end.
99Understanding %EOF in RPGLE File ProcessingLog in to accessWhat %EOF actually checks, and why it must be tested immediately after each READ for a read loop to work correctly.
100CHAIN for Keyed AccessLog in to accessHow to use CHAIN to look up one specific record in a keyed physical file by its key value.
101Understanding %FOUND after CHAINLog in to accessWhat %FOUND actually checks, and why it must be tested immediately after every CHAIN before using its fields.
102Writing Records with WRITELog in to accessHow to use WRITE to add a new record to a physical file, and how this differs from the WRITE used with display files.
103Updating Records with UPDATELog in to accessHow to use UPDATE to save changes to a record that was already successfully retrieved with CHAIN.
104Deleting Records with DELETELog in to accessHow to use DELETE to remove a record already retrieved with CHAIN, completing the basic native RPGLE file operations.
105SETLL in RPGLELog in to accessHow to use SETLL to position a keyed file at a specific key value, and how this differs from CHAIN.
106READE for Reading Matching KeysLog in to accessHow to use SETLL together with READE to read every record sharing the same key value.
107READP and Reading BackwardLog in to accessWhat READP does at a basic level, and how reading backward through a keyed file differs from reading forward.
108Processing Duplicate Keys in RPGLELog in to accessWhat a duplicate key is, and how to use SETLL and READE together to process every record sharing one key value.
109Basic File Locking Concept in RPGLELog in to accessWhat a record lock is at a beginner level, why IBM i uses them, and how they relate to UPDATE and DELETE.
110Handling File I/O Errors at a Beginner LevelLog in to accessThe beginner-level approach to handling file I/O errors, building on %FOUND, %EOF, and the general error-handling pattern.
111Debugging RPGLE File I/O ProgramsLog in to accessApplying dsply tracing, the ILE source debugger, and job logs specifically to problems in file I/O code.
112Common RPGLE File I/O Mistakes and Best PracticesLog in to accessThe most common beginner mistakes across native RPGLE file I/O, and a simple set of best practices to avoid them.