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

2. The Relational Model Broad, flexible model
Basis for almost all DBMS products
E.F. Codd defined well-structured “normal forms” of relations, “normalization”
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3. 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
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5. Functional Dependency
“relationship between or among attributes”
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Figure 5-2
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6. 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
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8. Combination Key
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Figure 5-4
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9. Normalization
“the process of evaluating and converting a relation to reduce modification anomalies”
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10. 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. 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
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13. Second Normal Form
“when all of a relation’s nonkey attributes are dependent on all of the key”
Figure 5-5
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14. Third Normal Form
“if it is in second normal form and has no transitive dependencies”
Figure 5-7
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15. Boyce-Codd Normal Form
“if every determinant is a candidate key”
Figure 5-8
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16. Fourth Normal Form “if in BCNF and has no multi-value dependencies”
Figure 5-11
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17. Fifth Normal Form ?
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18. 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. 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
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21. DK/NF Example
Figure 5-15
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22. DK/NF Example
Figure 5-16
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23. Summary of Normal Forms
Figure 5-18
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24. 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
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26. Optimization
De-Normalization
Controlled Redundancy
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