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Normalization. Courtesy of Dr. John Mote. Normalization “Rules”. 1 Field Uniqueness 2 Primary Keys 3 Functional Dependence 4 Field Independence. Normalization “Rules”. Field Uniqueness Each field in a table should represent a unique type of information Eliminate compound fields

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normalization

Normalization

Courtesy of Dr. John Mote

normalization rules
Normalization “Rules”

1 Field Uniqueness

2 Primary Keys

3 Functional Dependence

4 Field Independence

normalization rules3
Normalization “Rules”
  • Field Uniqueness
    • Each field in a table should represent a unique type of information
    • Eliminate compound fields
    • Eliminate repeating fields
compound fields
Compound Fields

SSN

Name

Address

123-45-6789

987-65-4321

111-22-3333

Bob White

Jaye Byrd

C. Gull

708 Pine, San Antonio, Texas, 78201

5127 Maple, Austin, Texas, 78712

1300 Teak, San Antonio, Texas, 78201

compound fields5
Compound Fields

SSN

Name

Children

123-45-6789

987-65-4321

111-22-3333

Bob White

Jaye Byrd

C. Gull

Mary, James, Kenneth

Thomas, Leslie

repeating fields
Repeating Fields

SSN

Name

Child-1

Child-2

Child-3

Child-4

123-45-6789

987-65-4321

111-22-3333

Bob White

Jaye Byrd

C. Gull

Mary

Thomas

---------

James

Leslie

---------

Kenneth

---------

---------

---------

---------

---------

normalization rules7
Normalization “Rules”
  • Field Uniqueness
  • Primary Keys
    • Each table must have a primary key
    • “Natural” keys
    • System-generated keys
normalization rules8
Normalization “Rules”
  • Field Uniqueness
  • Primary Keys
  • Functional Dependence
    • For each unique primary key value, the values in the data columns must be relevant to, and must completely describe, the subject of the table
normalization rules9
Normalization “Rules”
  • Field Uniqueness
  • Primary Keys
  • Functional Dependence
    • For each unique primary key value, the values in the data columns must be relevant to, and must completely describe, the subject of the table
    • What?
functional dependence
Functional Dependence

SSN

Name

Pay Date

Earnings

123-45-6789

Bob White

Nov 1998

$4,800

Composite Primary Key

functional dependence11
Functional Dependence

SSN

Name

Pay Date

Earnings

123-45-6789

987-65-4321

123-45-6789

111-22-3333

123-45-6789

987-65-4321

111-22-3333

Bob White

Jaye Byrd

Bob White

C. Gull

Bob White

Jaye Byrd

C. Gull

Nov 1998

Dec 1998

Dec 1998

Dec 1998

Jan 1999

Nov 1998

Jan 1999

$4,800

$2,750

$5,125

$4,000

$5,125

$3,300

$4,000

functional dependence12
Functional Dependence

SSN

Name

SSN

Pay Date

Earnings

123-45-6789

987-65-4321

111-22-3333

Bob White

Jaye Byrd

C. Gull

123-45-6789

987-65-4321

123-45-6789

111-22-3333

123-45-6789

987-65-4321

111-22-3333

Nov 1998

Dec 1998

Dec 1998

Dec 1998

Jan 1999

Nov 1998

Jan 1999

$4,800

$2,750

$5,125

$4,000

$5,125

$3,300

$4,000

normalization rules13
Normalization “Rules”
  • Field Uniqueness
  • Primary Keys
  • Functional Dependence
    • For each unique primary key value, the values in the data columns must be relevant to, and must completely describe, the subject of the table
normalization rules14
Normalization “Rules”
  • Field Uniqueness
  • Primary Keys
  • Functional Dependence
  • Field Independence
    • You must be able to make a change to the data in any field (other than the primary key) without affecting any other field
field independence
Field Independence

SSN

Name

City

State

Zip

123-45-6789

987-65-4321

111-22-3333

Bob White

Jaye Byrd

C. Gull

San Antonio

Austin

San Antonio

Texas

Texas

Texas

78201

78712

78201

field independence16
Field Independence

SSN

Name

Zip

123-45-6789

987-65-4321

111-22-3333

Bob White

Jaye Byrd

C. Gull

78201

78712

78201

City

State

Zip

San Antonio

Austin

Texas

Texas

78201

78712

normalization rules17
Normalization “Rules”

1 Field Uniqueness

2 Primary Keys

3 Functional Dependence

4 Field Independence