stored on disk drives. That is the domain of the physical schema. Now logical schemas describe data in terms of relational tables and columns, object-oriented classes, and XML tags. A single set of tables, for example, can be implemented in numerous ways, up to and including an architecture where table rows are maintained on computers in different countries. See also Database schema Conceptual data model Logical data model References External links FEA Consolidated Reference Model Document (whitehouse.gov) Oct 2007. Data modeling Data management ja:スキーマ (データベース)