This is the core of moving data from one (legacy) system to another (new or target) system. At a field by field level we need to know where each byte of data is coming from, where it is going to and what we need to do to reshape it on the way through.
A Data Mapping is the rule by which one or more data items in a Legacy Data Store will have their values moved to one or more items in the new system database.
In the overwhelming majority of cases, this involves a one-to-one match of legacy to target. However, as the definition suggests, this may involve splitting a value in one data store into a number of values in ...