The problem that exists is large database systems (e.g., federations, warehouses) have several virtual or physical databases, each derived from other layers. Today, metadata tend to be locked into the schema where it is supplied, and are rarely available through other schemas. Globalizing the metadata is a long-term challenge, which raises many research problems, such as: Identify inference and "view update" rules for all types of metadata and operations [4]. Design a framework system into which rules can be plugged. Design the administrator's interface. Services for negotiating about metadata values (or data values) among autonomous administrators, e.g., what-if analyses, suggesting changes Algorithmics: wizards to implicitly enumerate a large set of queries equivalent to a view definition.