Page 150 - DCAP402_DCAO204_DATABASE MANAGEMENT SYSTEM_MANAGING DATABASE

Unit 8: Normalization

Definition of Fifth Normal Form Notes

A table should be in fifth normal form (5NF) if and only if every join dependency in the table is
implied by the candidate keys of the table.

Table before Fifth Normal Form

Dept. Subject Student
Comp. Sc. CP1000 John Smith
Mathematics MA1000 John Smith
Comp. Sc. CP2000 Arun Kumar
Comp. Sc. CP3000 Reena Rani
Physics PHI 000 Raymond Chew
Chemistry CH2000 Albert Garcia

Table after Fifth Normal Form
Dept-Subject

Dept. Subject Student
Comp. Sc. CP1000 John Smith
Mathematics MA1000 John Smith
Comp. Sc. CP2000 Arun Kumar
Comp. Sc. CP3000 Reena Rani
Physics PHI 000 Raymond Chew
Chemistry CH2000 Albert Garcia

Subject-Student

Subject Student
CP1000 John Smith
MA 1000 John Smith
CP2000 Arun Kumar
CP3000 Reena Rani
PHI 000 Raymond Chew
CH2000 Albert Garcia

Dept-Student

Dept. Student
Comp. Sc. John Smith
Mathematics John Smith
Comp. Sc. Arun Kumar
Comp. Sc. Reena Rani
Physics Raymond Chew
Chemistry Albert Garcia

The fifth normal form is also called Project-Join Normal Form (PJNF).

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