A transformation is a set of mappings between the source data items and the target data items. This determines how and where each data item from the source database is placed in the target database. After the transformation is defined in the DDW, you must deploy it to the Administration Site and then perform either a bulk data transformation or a changed data transformation.

Performing a bulk data transformation is optional; however, if you want to perform both bulk data transformation and changed data transformation, then it is recommended to first perform a bulk data transformation to transform the historical data and then start a changed data transformation to transform the new changes.

Bulk Data Transformation: A bulk data transformation is the process of transforming the historical data from the transformation source to the transformation target, based on the defined transformations. You could perform a bulk data transformation before performing a changed data transformation.

Changed Data Transformation: A changed data transformation is a near real-time process to move the changed data from a transformation source to a transformation target based on the defined transformations.

After you initiate a changed data transformation, Data Exchange provides a continuous data feed of the selected record updates of the transformation source to the transformation target.