Normalisation

Normalisation is to find out the entities and attributes within given data.

5 steps of Normalisation

1. Write down the unnormalised data
2. choose key for main group
3. extract repeating groups into separate entities and choose key
4. identify and extract partial key dependencies
5. identify and extract non key dependencies

0NF - write down all of the unnormalised data. once used data first then data that is used more than once appears second

1NF - choose keys for the data in the list (what is needed for the data to connect)

2NF - extract partial key dependencies (what remaining from the seperate entities do not depend on the key it is under)

3NF - extract non key dependencies (what is remaining from the seperate entities that could be used as a seperate entity on their own)

Lecture 2 and ERD

The learning objectives for todays lecture was having a clear understanding of:

• the four principles of data modelling
• the difference in modelling techniques
• terminology and notation
• the 6 steps and objectives for ERD models.

4 principles of ER modelling are:

1. Identification of entities, relationship and structure
2. gives a process independant model
3. should result in a minimal data model
4. gives a logical model

6 steps of creating a good ERD:

1. identify entities
2. identfy each entities' attribute
3. put the data in logical groups
4. identify the primary keys
5. remove redundant data
6. identify and add relationships

:) Sam (:

Welcome

My name is Samantha Leonard and I used to go to Stockton Sixth Form College. I completed an ICT A Level, a Business Studies A level and also a Mathematics AS level.

I enjoy hanging out with friends and just generally having a good laugh! I hate being sad!...sad is bad!

Good luck to everyone with the course, Speak to you soon!

Sam x