Please use this identifier to cite or link to this item: http://hdl.handle.net/1880/46289
Title: POLYGONAL JOIN DEPENDENCIES, CLOSED CO-RELATIONSHIP CHAINS AND THE CONNECTION TRAP IN RELATIONAL DATA BASES
Authors: Bradley, James
Keywords: Computer Science
Issue Date: 1-Jan-1987
Abstract: Co-relationships between relations occur when both attributes supporting the relationship are non primary keys. A co-relationship can have at least three levels of semantic significance. A special case arises when relations are linked in a closed chain by co-relationships that have existential semantic significance. For binary relations in such a closed chain, it is shown that there is a fundamental theorem that prohibits extraction of reliable information from a complete join of the relations, unless the join contains a polygonal join dependency of order equal to the number of relations in the chain. Users who ignore this restriction fall into a sophisticated connection trap.
URI: http://hdl.handle.net/1880/46289
Appears in Collections:Bradley, James

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