csce520-lect6 - Normalization ReadingAssignments

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Normalization
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Farkas CSCE 520 2 Reading Assignments Database Systems The Complete Book: Complete  Chapters 3 Following lecture slides are modified from Jeff  Ullman’s slides for Fall 2002 -- Stanford  
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Farkas CSCE 520 3 Closures Closure of attributes (A + ): find keys Closure of FDs (S + ): projection of FDs to  decompositions of schema Canonical cover:  minimize the number of  functional dependencies Important for updates
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Farkas CSCE 520 4 Problems of Relational Database  Design Loss of information (lossless-join) Inability to represent certain information  (dependency preservation) Repetition of information (normal forms)
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Farkas CSCE 520 5 Desirable Properties of Decomposition  – Lossless-join  Lossless-Join Let R be a relation schema, S a set of FDs on R,  R1 and R2 a decomposition of R.  R1 and R2 form a lossless-join decomposition if  at least one of the following functional  dependencies are in S + R1   R2   R1 R1   R2   R2
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Farkas CSCE 520 6 Decomposition and FDs Functional dependencies : can be used in  designing a relational database to remove  the undesired properties Normalization using FDs: Boyce-Codd Normal Form (BCNF) 3 rd  Normal Form (3NF)
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This note was uploaded on 12/13/2011 for the course CSCE 522 taught by Professor Farkas during the Fall '11 term at South Carolina.

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csce520-lect6 - Normalization ReadingAssignments

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