منابع مشابه
Complete Geometric Query Languages
We extend Chandra and Harel s seminal work on computable queries for re lational databases to a setting in which also spatial data may be present using a constraint based data model Concretely we introduce both coordinate based and point based query languages that are complete in the sense that they can express precisely all computable queries that are generic with respect to certain classes of...
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The relational model has recently been extended to so-called K-relations in which tuples are assigned a unique value in a semiring K. A query language, denoted by RA+K, similar to the classical positive relational algebra, allows for the querying of K-relations. We study the completeness of RA+K in the sense of Bancilhon and Paredaens (BP) and show that RA+K is, in general, not BP-complete. Fac...
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ژورنال
عنوان ژورنال: Journal of Computer and System Sciences
سال: 1999
ISSN: 0022-0000
DOI: 10.1006/jcss.1999.1630