A Polygen Data Model for data source tagging in Composite Information Systems

Includes bibliographical references (p. 15-18).Work supported in part by MIT's International Financial Service Research Center, MIT's Center for Information Systems Research, and MIT's LCS Digital Library Project.Y. Richard Wang, Stuart E. Madnick

A polygen model for heterogeneous database systems : the source tagging perspective

Includes bibliographical references (p. 26-29).Supported in part by MIT's Financial Service Research Center, MIT's Center for Information Systems Research, and MIT's LCS Digital Library Project.Y. Richard Wang, Stuart E. Madnick

A Semantics for Complex Objects and Approximate Answers

AbstractA new definition of complex objects is introduced which provides a denotation for incomplete tuples as well as partially described sets. Set values are “sandwiched” between “complete” and “consistent” descriptions (respectively represented in the Smyth and Hoare powerdomains), allowing the maximal values to be arbitrary subsets of maximal elements in the domain of the space of descriptions. We then restrict our attention to complex objects which are in some sense “natural,” i.e., those which represent “views” of entity-relationship databases, and define rules over these objects. The rules can be used not only as an integrity check on the information in the database, but can be used constructively to infer consistent instances of conclusions and to refine complete instances of the hypothesis. The system is shown to extend the power of datalog (without negation) and the relational algebra (with set difference), and to have an efficient implementation