Entity Relationship Modelling
Computer Science: OCR A Level, topic 3.2.4
Entity Relationship Modelling
When you are working with a relational database and forming relationships, you are linking entities together. This is known as entity relationship modelling.
Entity relationship modelling
- There are 3 main types of relationships that exist:
- One to one.
- One to many.
- Many to many.
- We can show these relationships in entity relationship diagrams.
One to one
- A one to one relationship is when one entity is linked to one other entity.
One to many
- A one to many relationship is when one entity is linked to several entitities.
Many to many
- A many to many relationship is when several entities are linked to several other entitities.
Test yourself on Entity Relationship Modelling
Which type of entity relationship is modelled using the diagram shown?
Which type of entity relationship is modelled using the diagram shown?
Which type of entity relationship is modelled using the diagram shown?