EXTENSIONAL ISSUES IN SCHEMA INTEGRATION

摘要

To form a Cooperative Information System in which several pre-existing information. systems cooperate by means of database interoperability, a methodology for database schema integration is needed. Extensional issues should be taken into account in such a methodolo gy. We show how objects in different databases that represent the same real world object may be correlated through an object identification function (pif), and collapsed in external classes, when there are no dependencies between the component databases. We also extend oxir methodology to deal with those cases in which, in addition to this oif, existence interdepend-encies are to be specified and enforced. The powerful abstractions of our BLOOM model are used in both cases.