Information Modeling and Relational Databases, 2nd Edition

Chapter Notes

Schema equivalence has been studied within the relational model (e.g., Kobayashi 1986, 1990), the ER model (e.g., D’Atri and Sacca 1984), EER models (e.g., Batini et al. 1992) and UML (e.g., Blaha and Premerlani 1998). To keep our treatment intuitive, some technical issues have been glossed over. More formal treatments of schema transformation in ORM may be found in Halpin (1989b, 1991b) and Halpin and Proper (1995a). For formal proofs of some conceptual schema equivalences, see Halpin (1989b). Further reduction transformations and additional ORM constraints (e.g., unique-where-true constraints) are discussed by Halpin, Carver, and Owen (2007).

Most work on schema optimization focuses on subconceptual levels. Date (2000) provides ...