This is an introduction to Normalisation

1. NORMALISATION
Definition
Normalisation is a process of breaking down complex table structures to simpler forms.
In a way, normalisation can be explained as a mathematical technique for analysing data.

2. REASONS FOR THE NORMALISATION PROCESS
1. Normalisation minimises the duplication of data
2. The normalised data enables the data model to be mapped
onto a wide variety of different database designs
3. The final tables in third normal form may provide the flexibility
to enable data to be extracted efficiently.

3. EXAMPLE OF NORMALISATION PROCESS
Here is a simple database containing the records of students in a college. The assumption is that
database would contain the data in an un-normalised form:
Un- normalised data
STUDENT
Student_reference
Surname
Forenames
Address
Tel_no
Course_number
Course_title
Lecturer_name
Lecturer_number

4. 1NF, 2NF & 3NF
Data in first normal form will appear as shown below:
STUDENT (Student ref, Surname, Forenames, Address, Telephone number)
ENROLMENT (Student ref, Course number, Course title, Lecturer name, Lecturer number)
Data in second normal form will appear as shown below:
STUDENT (Student ref, Surname, Forenames, Address, Telephone number)
ENROLMENT (Student ref, Course number, Course title, Lecturer name, Lecturer number)
COURSE (Course number, Course title)
Data in third normal form will appear as shown below:
STUDENT (Student ref#, Surname, Forenames, Address, Telephone number)
ENROLMENT (Student ref , Course number, Course title, Lecturer name, Lecturer number)
COURSE (Course number#, Course title)
LECTURER (Lecturer number#, Lecturer name)