PeopleCode Execution in Pages with Multiple Scroll Areas
Components with multiple levels can have multiple rows of data from multiple primary record definitions. You must know the order in which the system processes buffers for this data, because it applies PeopleCode in the same order.
The Component Processor uses a depth-first algorithm to process rows in multiple-scroll-area pages, starting with a row at level zero, drilling down to dependent rows on lower levels, and then working up the hierarchy until the system has processed all the dependent rows of the last row on the highest level.
Scroll Level One
When pages have only one scroll bar, the Component Processor processes record definitions at scroll level zero, and then all rows of data at scroll level one.
Data is retrieved for all rows with a single Select statement, and then it is merged with buffer structures.
Scroll Level Two
With scroll bars at multiple scroll levels, the system processes a single row of data at scroll level one, and then it processes all subordinate rows of data at scroll level two. After processing all subordinate data at scroll level two, it processes the next row for scroll level one, and all the subordinate data for that row. The system continues in this fashion until all data is processed.
Scroll Level Three
The Component Processor uses the same method for processing subordinate data at scroll level three. Data is retrieved for all rows with a single Select statement, and then merged with buffer structures. The Component Processor processes a single row of data at scroll level two, and it processes all subordinate data at scroll level three. After processing all subordinate data at scroll level three, it processes the next row for scroll level two and all the suboridinates data for that row. The system continues in this fashion until all data is processed..