Customer Reviews

Essentials of Subfile Programming and Advanced Topics in RPG IV

5 star:		(2)
4 star:		(0)
3 star:		(0)
2 star:		(0)
1 star:		(0)

 

 

I used Phil Levinson's book after graduating with an As/400 degree. The subfile book is essential, and unique. It is the only on of it's kind to go into such detail about subfiles. The examples are easy to understand. The entire book and exercises takes you step by step so you can follow and learn. I would recomend this book to anyone who is new at using subfiles.

Essentials of Subfile Programming, Phil Levinson

Philip J. Levinson has 15 years experience as an AS/400 programmer/analyst, consultant, and programming teacher at Jefferson College. He has a bachelor's degree in Mechanical Engineering and a master's degree in Management. This 260 page book has twelve chapters, three appendices, and an Index. Subfiles are the tool to support displaying lists of data on the screen. Journaling and commitment control will protect database integrity when records are changed. The application is for inventory control of a bookstore. Chapter 1 will show how to create subfile records and how to load, display, and clear a subfile. Chapter 2 shows how to delete and change records for interactive file maintenance. There are three methods for loading subfiles with multiple lists (Chapter 3). The next chapter shows how to display multiple lines per record.

Chapter 5 shows ways to locate records and load the desired data into the subfile. There are ways to make the system more user friendly and include the Help screens (Chapter 6). You can use subfiles in windows to provide advanced prompting features for users (Chapter 7). Chapter 8 has advanced concepts in linking RPG programs and database files. Chapter 9 shows the file-information and program-status data structures for normal processing and error handling. Error handling is explained in greater depth in Chapter 10. Chapter 11 explains journaling and commitment control to improve data integrity at the program and transaction levels. Data queues are explained in Chapter 12, they provide program-to-program communication.

An organization has standards for libraries and naming conventions (Appendix A). The author provides many practical suggestions for program arrangement and documentation. Appendix B offers good advice on testing and debugging programs. The best code is clean and easy to maintain. "Change is the only constant" said Heraclites. Appendix C explains how to use Screen Design Aid (SDA) to create, test, and edit displays.