لطفا منتظر باشید ...
Chapter 4: Adding Business Logic with the Formula Workshop
Overview
Formula language programming is an adventure of the best kind: It’s creative and fun, and there’s no risk of hurting yourself! Programmers from the end-user level through the professional-developer level and all the levels in between write code to add functionality where none initially existed. Some write code because it’s their hobby and they like making a computer do new and interesting things. Most, however, write code to fulfill a business need.The most powerful person in report writing is one who has personal understanding of the meaning of the data from a business perspective, has the ability to write formula code to manipulate it, and has the skill to lay out the report in an organized and visually pleasing way. In this chapter, we’ll build the foundation you need to master the formula languages built into Crystal and use them effectively in a report to do tasks such as adding a calculated value directly to a report, coding record-selection criteria to affect data retrievals, creating group-selection formulas, formatting sections and other report elements based on conditions, searching for data in a previewed report, building a running total field, and adding alert messages to reports based on condition criteria.Featured in this chapter:
Understanding core concepts in formula programming
Using formulas in Crystal Reports
The Report Explorer
The Formula Workshop and Workshop Tree
The Formula Expert and the Formula Editor
Writing code using Basic Syntax and Crystal Syntax
Using operators and built-in functions
Programming custom functions
Understanding evaluation time issues
Troubleshooting formulas
