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Chapter 5
Database Design 1:
Normalization
Concepts of Database Management, 4th Edition, Pratt & Adamski
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Objectives
 Discuss
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functional dependence
 Define
first normal form, second normal
form, and third 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
Concepts of Database Management, 4th Edition, Pratt & Adamski
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Objectives
 Discuss
the problems associated with
incorrect conversions to third normal
form
 Define
fourth normal form
 Describe
the problems associated with
tables (relations) that are not in fourth
normal form and describe the mechanism
for converting to fourth normal form
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Functional Dependence
 Column
B is functionally dependent on
Column A if A’s value determines a single
value for B at a given time
 Given
A, a single value for B can be
determined
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Functional Dependence Example
Figures 5.3 - 5.4
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Rep Table Where LastName can determine record
Rep Table Where LastName cannot determine record
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Keys
 Column(s)
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C is primary key for table T if:
Property 1: All columns in T are functionally dependent
on C
Property 2: No subcollection of columns in C (assuming
C is a collection of columns and not just a single
column) also has Property 1
 Candidate

Column(s) on which all other columns in table are
functionally dependent
 Alternate

Keys
Keys
Candidate keys not chosen as primary keys
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First Normal Form (1NF)
 Unnormalized

table
Contains a repeating group
 Table

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in 1NF
Contains no repeating groups
 Removal
of repeating groups is starting
point in quest for problem-free tables
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1NF Example
Figure 5.5
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Unnormalized Table
Concepts of Database Management, 4th Edition, Pratt & Adamski
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1NF Example (con’t.)
Figure 5.6
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Conversion to 1NF
Concepts of Database Management, 4th Edition, Pratt & Adamski
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Second Normal Form (2NF)
 1NF


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Tables may contain problems
Redundancy
Update Anomalies
 Update,
inconsistent data, additions, deletions
 Occur because a column is dependent on a portion
of a multi-column primary key
 2NF

Table
In 1NF and no nonkey column is dependent on
only a portion of the primary key
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Dependency Diagram for Orders
Figure 5.8
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2NF Example
Figure 5.9a
Concepts of Database Management, 4th Edition, Pratt & Adamski
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2NF Example
Figure 5.9b
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Third Normal Form (3NF)
 2NF


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Tables may still contain problems
Redundancy and wasted space
Update Anomalies
 Update,
inconsistent data, additions, deletions
 Occur because a column is dependent on a portion
of a multi-column primary key
 3NF

Table
In 2NF and the only determinants contained are
candidate keys
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Customers Dependency Diagram
Figure 5.11
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3NF Example
Figure 5.12a
Concepts of Database Management, 4th Edition, Pratt & Adamski
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3NF Example
Figure 5.12b
Concepts of Database Management, 4th Edition, Pratt & Adamski
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Incorrect Decomposition Example
Figure 5.13a
Concepts of Database Management, 4th Edition, Pratt & Adamski
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Incorrect Decomposition Example
Figure 5.13b
Concepts of Database Management, 4th Edition, Pratt & Adamski
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2nd Incorrect Decomposition
Figure 5.14a
Concepts of Database Management, 4th Edition, Pratt & Adamski
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2nd Incorrect Decomposition
Figure 5.14b
Concepts of Database Management, 4th Edition, Pratt & Adamski
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Fourth Normal Form (4NF)
 3NF


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Tables may still contain problems
Dependencies
Update Anomalies
 Update,
additions, deletions
 Occur because of multivalued dependencies
 4NF

Table
In 3NF and has no multivalued dependencies
Concepts of Database Management, 4th Edition, Pratt & Adamski
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Incorrect 4NF Example
Figure 5.15
Concepts of Database Management, 4th Edition, Pratt & Adamski
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4NF Example
Figure 5.16a
Concepts of Database Management, 4th Edition, Pratt & Adamski
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4NF Example
Figure 5.16b
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Normal Forms
Figure 5.17
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