Read Rows from JDBC works like any dataset. One row at a time is read.
The test contains a loop to the step to indicate that the next row should be read.
Configurations within the step indicate what to do when the end of data is reached.
In the example below, a dataset is read. The "More Steps" step loops back to the dataset indicating read the next row.
At end of dataset, the logic branches to "Last Step if Necessary" to perform an action and the test case ends.