Different business units often want aggregate, filter, join and transform data in different ways - sometimes in ways that are hard to anticipate. In general, t

Different business units often want aggregate, filter, join and transform data in different ways - sometimes in ways that are hard to anticipate. In general, the closer to the persistence layer you can perform those transformations, the better they will scale. If you pull the transform into the app layer, you need to move and serialize more data. If you pull the transformation into a constellation of apps, you need to move and serialize a constellation of data. (edit: formatting)