One of the principal advantages of the NAV report is its built-in data flow structure. At the beginning of any report, we will define the DataItems (the tables) that the report will process. We can create a processing-only report that has no data items (if no looping through database data is required), but that situation often calls for a code unit to be used. In a report, NAV automatically creates a data flow process for each DataItem or table reference. This automatically created data flow provides specific triggers and processing events for each data item, as follows:
- Preceding the DataItem
- After reading each record of the DataItem
- Following the end of the DataItem
The underlying black-box report logic (the part we can't see or affect) automatically loops through the named tables, reading and processing one record at a time. Therefore, any time we need a process that steps through...