Slides in this set

Slide 1

Preview of page 1

AS ICT, OCR, chapter 5…read more

Slide 2

Preview of page 2

Normalisation features
1st normal form
· No repeating fields of data
· Each field is atomic (data that's been broken down
into the smallest units possible, without loosing
· Each row is unique (primary key)
· Each field has a unique name
2nd normal form
· Must be in 1NF
· All non key fields must depend on the primary key…read more

Slide 3

Preview of page 3

Normalisation features
3rd normal form
· Must be in 2NF
· No attribute should depend on any other non key
attribute…read more

Slide 4

Preview of page 4

Advantages and disadvantages
Advantages Disadvantages
Removes redundancy- less data that isn't Reduced performance- normalised data
needed, less duplicate data, saves storage takes longer to sort through
Increases consistency- makes searching Problems with historical data- some
for data easier historical data may require certain values
to be stored twice to act as references
Increases integrity
Easier maintenance- makes sure data is
reliable when updated
Flexibility for future expansion- database
can be easily updated…read more


No comments have yet been made

Similar ICT resources:

See all ICT resources »