This document discusses the relational model and normalization in database design. It introduces key concepts like relations, functional dependencies, keys, and normal forms. The goal of normalization is to reduce data anomalies by converting relations into first, second, third, and higher normal forms based on evaluating and removing functional dependencies between attributes. Higher normal forms help prevent more types of modification anomalies.

1. Chapter 5
The Relational Model and
Normalization
David M. Kroenke
Database Processing
© 2000 Prentice Hall

2. Chapter 5
© 2000 Prentice Hall
The Relational Model
• Broad, flexible model
• Basis for almost all DBMS products
• E.F. Codd defined well-structured
“normal forms” of relations,
“normalization”
Page 113

3. Chapter 5
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Relation
• Two-dimensional table
• Rows are tuples
• Columns are attributes
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4. Equivalent Relational Terms
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Figure 5-1 © 2000 Prentice Hall

5. Functional Dependency
“relationship between or among
attributes”
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Figure 5-2 © 2000 Prentice Hall

6. Chapter 5
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Functional Dependency
Notation
SID  Major
ComputerSerialNumber  MemorySize
(SID, ClassName)  Grade
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7. Key
“a group of one or more attributes that
uniquely identifies a row”
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Figure 5-3 © 2000 Prentice Hall

8. Combination Key
Page 117
Figure 5-4 © 2000 Prentice Hall

9. Chapter 5
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Normalization
“the process of evaluating and
converting a relation to reduce
modification anomalies”
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10. Chapter 5
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Anomaly
“an undesirable consequence of data
modification in which two or more
different themes are entered
(insertion anomaly) in a single row or
two or more themes are lost if the
row is deleted (deletion anomaly)”
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11. Chapter 5
© 2000 Prentice Hall
Normal Forms
“classes of relations and techniques for
preventing anomalies”
DK/NF = Domain Key Normal Form
(free of modification anomalies)
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12. First Normal Form
“any table of data that meets the
definition of a relation”
Figure 5-3 © 2000 Prentice Hall

13. Second Normal Form
“when all of a relation’s nonkey attributes
are dependent on all of the key”
Figure 5-5 © 2000 Prentice Hall

14. Third Normal Form
“if it is in second normal form and has
no transitive dependencies”
Figure 5-7 © 2000 Prentice Hall

15. Boyce-Codd Normal Form
“if every determinant is a candidate key”
Figure 5-8 © 2000 Prentice Hall

16. Fourth Normal Form
“if in BCNF and has no multi-value
dependencies”
Figure 5-11 © 2000 Prentice Hall

17. Chapter 5
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Fifth Normal Form
?
Page 125

18. Chapter 5
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Domain Key Normal Form
“if every constraint on the relation is a
logical consequence of the definition
of keys and domains”
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19. Chapter 5
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DK/NF Terms
• Constraint “a rule governing static
values of attributes”
• Key “unique identifier of a tuple”
• Domain “description of an
attribute’s allowed values”
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20. DK/NF Example
Figure 5-13 © 2000 Prentice Hall

21. DK/NF Example
Figure 5-15 © 2000 Prentice Hall

22. DK/NF Example
Figure 5-16 © 2000 Prentice Hall

23. Summary of Normal Forms
Figure 5-18 © 2000 Prentice Hall

24. Chapter 5
© 2000 Prentice Hall
A  B relationships
A  B and B  A one-to-one
A  B but B not  A many-to-one
A not  B and B not  A many-to-many
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25. Summary of Relationships
Figure 5-19 © 2000 Prentice Hall

26. Chapter 5
© 2000 Prentice Hall
Optimization
• De-Normalization
• Controlled Redundancy
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