Simultaneous searching across multiple data sets

A method and apparatus for indexing, searching, and retrieving data from data sets. Data sets may reside in the same database or be distributed across different databases. Data sets, whether within the same or distributed databases, may have the same format or heterogeneous formats. Source data sets are represented with mapping tables and inverted or index tables. Native fields of databases described in source tables are mapped to international or specialized standards. Source data fields that map to the standard field searched upon are identified, and objects satisfying a query's request are identified based upon the standard fields searched. Values are retrieved from the identified objects.