Sách Relational Database Design Algorithms and Further Dependencies

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Relational Database Design Algorithms and Further Dependencies (66 pages)

Relation Decomposition and Insufficiency of Normal Forms (cont.): Attribute preservation condition: Each attribute in R will appear in at least one relation schema Ri in the decomposition so that no attributes are “lost”. Another goal of decomposition is to have each individual relation Ri in the decomposition D be in BCNF or 3NF. Additional properties of decomposition are needed to prevent from generating spurious tuples