Local as View (LAV)

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

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

LAV reformulation amounts approximately to solving an equation that may have several solutions and it is more complicated than GAV. LAV is sometimes called rewriting-with-views. In a data integration scenario, it corresponds to different sources registering their mappings to the public schema, with possible overlapping.