ch050 - Concepts of Database Management Sixth Edition...

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Concepts of Database Management Sixth Edition Chapter 5 Database Design 1: Normalization
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Concepts of Database Management 2 Objectives Discuss functional dependence and primary keys Define first normal form, second normal form, and fourth normal form Describe the problems associated with tables (relations) that are not in first normal form, second normal form, or third normal form, along with the mechanism for converting to all three Discuss the problems associated with incorrect conversions to third normal form
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Concepts of Database Management 3 Objectives (continued) Describe the problems associated with tables (relations) that are not in fourth normal form and describe the mechanism for converting to fourth normal form Understand how normalization is used in the database design process
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Concepts of Database Management 4 Introduction Normalization process Identifying potential problems, called updating anomalies, in the design of a relational database Methods for correcting these problems Normal form : table has desirable properties First normal form (1NF) Second normal form (2NF) Third normal form (3NF) Fourth normal form (4NF)
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Concepts of Database Management 5 Introduction (continued) Normalization Table in first normal form better than table not in first normal form Table in second normal form better than table in first normal form, and so on Goal: new collection of tables that is free of update anomalies
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Concepts of Database Management 6 Functional Dependence Column B is functionally dependent on column A Each value for A is associated with exactly one value of B A → B A functionally determines B
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Concepts of Database Management 7 Functional Dependence (continued) FIGURE 5-2: Rep table with additional column, PayClass
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Concepts of Database Management 8 Functional Dependence (continued) FIGURE 5-4: Rep table with second rep named Kaiser added FIGURE 5-3: Rep table
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Concepts of Database Management 9 Keys Column A (or a collection of columns) is the primary key for a relation R Property 1: all columns in R are functionally dependent on A Property 2: no subcollection of columns in A also have Property 1 Candidate key: column(s) on which all columns in table are functionally dependent Alternate keys: candidate keys not chosen as primary key
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This note was uploaded on 10/20/2008 for the course IST 331 taught by Professor Sikder during the Spring '08 term at Cleveland State.

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ch050 - Concepts of Database Management Sixth Edition...

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