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Lecture04b_NormalizationExamples_Spring2006

# Lecture04b_NormalizationExamples_Spring2006 - Chapter 5...

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1 5 Chapter 5 Database Design 1: Some Normalization Examples Spring 2006

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2 5 Dependencies: Definitions Multivalued Attributes (or repeating groups ): non- key attributes or groups of non-key attributes the values of which are not uniquely identified by (directly or indirectly) (not functionally dependent on) the value of the Primary Key (or its part). STUDENT Stud_ID Name Course_ID Units 101 Lennon MSI 250 3.00 101 Lennon MSI 415 3.00 125 Johnson MSI 331 3.00
3 5 Dependencies: Definitions Partial Dependency – when an non-key attribute is determined by a part, but not the whole, of a COMPOSITE primary key. CUSTOMER Cust_ID Name Order_ID 101 AT&T 1234 101 AT&T 156 125 Cisco 1250 Partial Dependency

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4 5 Dependencies: Definitions Transitive Dependency – when a non- key attribute determines another non-key attribute. EMPLOYEE Emp_ID F_Name L_Name Dept_ID Dept_Name 111 Mary Jones 1 Acct 122 Sarah Smith 2 Mktg Transitive Dependency
5 5 Normal Forms: Review Unnormalized – There are multivalued attributes or repeating groups 1 NF – No multivalued attributes or repeating groups. 2 NF – 1 NF plus no partial dependencies 3 NF – 2 NF plus no transitive dependencies

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6 5 Example 1: Determine NF ISBN Title ISBN Publisher Publisher Address BOOK ISBN Title Publisher Address All attributes are directly or indirectly determined by the primary key; therefore, the relation is at least in 1 NF
7 5 Example 1: Determine NF ISBN Title ISBN Publisher Publisher Address BOOK ISBN Title Publisher Address The relation is at least in 1NF. There is no COMPOSITE primary key, therefore there can’t be partial dependencies.

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