Informatica PowerCenter provides a utility called debugger to debug the mapping so that you can easily find the issue in the mapping you created. Using the debugger, you can see the flow of every record across the transformations.
As you are aware, Informatica PowerCenter is not a data storage tool, it is a data manipulation tool that helps you manipulate data. This point is important in the aspect of debugger, as once you finish the process, to verify the data, you only have either the source or the target to check the result and compare. The debugger jumps in with a functionality that provides you with the option of actually seeing the data flow from each and every transformation in your mapping.
When you execute the mapping through a session task, the data automatically starts flowing from the source to the target through transformations--the same process you are carrying out manually using the debugger.
Consider an example to understand the debugger functionality...