Explain the design steps in transaction mapping. 
-  Review the fundamental model. 
 
-  Review and refine the DFD for the software. 
 
-  Verify whether the DFD has the transform or transaction mapping. 
 
-  Identify transaction center and the flow characteristics along each of the action paths. 
 
-  Factor and refine the transaction structure and the structure of every action path. 
 
-  Refine the first iteration architecture using design heuristics for improved software quality.