Master data includes things like material masters, vendor masters, and customizing data that provide the base information needed for transactions. Transactional data are the events like purchase orders and invoices that change over time. The key differences are that master data remains constant but needs periodic updates, while transactional data always has a time dimension and numerical value referring to objects. Examples of master data include vendor and material masters used to create purchase orders, while examples of transactional data are financial orders and invoices.