Export database derivation in object-oriented wrappers

作     者：Lim, EP Lee, HK 

作者机构：Nanyang Technol Univ Sch Appl Sci Div Software Syst Singapore 639798 Singapore 

出 版 物：《INFORMATION AND SOFTWARE TECHNOLOGY》 (信息与软件技术)

年 卷 期：1999年第41卷第4期

页      面：183-196页

核心收录：

学科分类：08[工学] 0835[工学-软件工程] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

主　　题：interoperable databases legacy data object-oriented databases 

摘      要：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. (C) 1999 Elsevier Science B.V. All rights reserved.