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Mapping One-to-one Predicates to a Relational Schema

出版	Key Centre for Software Technology, Department of Computer Science, University of Queensland, 1992
URL	http://books.google.com.hk/books?id=JuY3GwAACAAJ&hl=&source=gbs_api

註釋Abstract: "A One-to-One dependency between two object types is often considered the simplest form of dependency; as such, its relational implementation, including the enforcement of constraints, has often been over-simplified. Traditionally, a 1:1 dependency is grouped as a 1:n or n:1 dependency with a preference to favouring fewer null values. In fact other alternatives exist each with its own set of update, query and constraint enforcement anomalies. This paper investigates various alternatives for mapping 1:1 predicates to a relational schema and the problems encountered when implementing the resulting schema; guidelines are provided to assist in choosing the preferred relational database design."