You can build logic into your maps by using rules, conditions, memory variables, system variables, cross-reference tables to control the mapping data
See
Chapter 13, “Mapping.”
Chapter 15, “Creating a Map Flow.”
Chapter 14, “Conditional Mapping.”
Chapter 20, “Working with Rules.”
Chapter 18, “Working with Memory Variables.”
Chapter 19, “Working with System Variables.”
Chapter 22, “Working with Cross-Reference Tables.”
