Once the deliverables have been refined, the Data can be mapped from the Source system to the Target Database. The target Physical Models defined provide the output fields required, their granularity, Data Type, Data length and the relationships between Fact and Dimension tables.
Data Mapping is concerned with the technical mapping of source to target tables. Again, in a Datawarehousing environment, these may require multiple mappings for numerous staging points. Data Mapping also provides the physical specifications for treating the Data on route to the Target Warehouse using a combination of filters, joins, aggregation and general data manipulation. Full mapping specifications should be documented and maintained throughout the Project Life.