 For any given entity, the master source must be identified (sometimes called the Golden Record).Any given system could publish (be the source of truth for) information on a particular entity (e.g., customer) and also subscribe to updates from another system for information on some other entity (e.g., product).An alternative approach is point-to-point data updates, but these become exponentially more expensive to maintain as the number of systems increases, and this approach is increasingly out of favour as an IT architecture.