Another advanced architectural approach is bi-directional Metadata Architecture, which allows Metadata to change in any part of the architecture (source, data integration, user interface), and then feedback is coordinated from the repository (broker) into its original source.
Various challenges are apparent in this approach. The design forces the Metadata repository to contain the latest version of the Metadata source and forces it to manage changes to the source, as well. Changes must be trapped systematically, and then resolved. Additional sets of process interfaces to tie the repository back to the Metadata source(s) must be built and maintained.
This figure illustrates how common Metadata from different sources is collected in a centralized Metadata store. Users submit their queries to the Metadata portal, which passes the request to a centralized repository. The centralized repository will try to fulfill the user request from the common Metadata collected initially from the various sources. As the request becomes more specific or the user needs more detailed Metadata then the centralized repository will delegate down to the specific source to research the specific details. Global search across the various tools is available due to the common Metadata collected in the centralized repository.