Export Database Derivation Approach for supporting Object-Oriented wrapper queries

• Main Authors: LIM, Ee Peng, LEE, Hon-Kuan
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 1996
• Subjects: Relational database systems; Object oriented programming; Information technology; Query languages; Data structures; Computational linguistics; Constraint theory; Export databases; Extent derivation structures; Legacy data; Interoperable databases; Databases and Information Systems; Numerical Analysis and Scientific Computing
• Online Access: https://ink.library.smu.edu.sg/sis_research/1024; https://ink.library.smu.edu.sg/context/sis_research/article/2023/viewcontent/ExportDBDerivationQueryProcessOOWrap_1996.pdf
• Institution: Singapore Management University

Wrappers export the schema and data of existing heterogeneous databases and support queries on them. In the context of cooperative information systems, we present a flexible approach to specify the derivation of object-oriented (OO) export databases from local relational databases. Our export database derivation consists of a set of extent derivation structures (EDS) which defines the extent and deep extent of export classes. Having well-defined semantics, the EDS can be readily used in transforming wrapper queries to local queries. Based on the EDS, we developed a wrapper query evaluation strategy which handles OO queries on the export databases. The strategy is unique in that it considers the limited query processing capabilities of local database systems as well as the language constraints on the local query languages.