Global as View (GAV)

In a global-as-view approach, or shortly, GAV, the view is expressed as a mapping from the storage(local) schema S to the public(global) schema P:

In other words, the view is a query against S which returns results expressed in P.

GAV reformulation of queries is also called composition-with-views: a query on the global schema can be run just by mapping all the elements of the global schema into the local schema(s) and changing the query accordingly.