An active transformation can change the number of rows that pass through it.

To define the number of rows in the output, call the generateRow() method in the code to generate each output row. You might choose to generate multiple output rows from a single input row or generate a single output row from multiple input rows. For example, if the transformation contains two input ports that represent a start date and an end date, you can call the generateRow() method to generate an output row for each date between the start date and the end date.

A passive transformation cannot change the number of rows that pass through the transformation. The transformation calls the generateRow() method to generate an output row after processing each input row.