This is the way I was schooled (although I guess different approaches to the design process will provide different views on the subject).
An Entity Relationship Diagram is a conceptual modelling tool used early on in a database design process. It is a way of gathering the thoughts about what information is needed and different bits of information are related.
The Relationships view in Access is the physical model i.e. the model that is actually implemented. Also, the Relationship view lacks some of the semantics often used in ERDs. If you google ERD then you’ll see some examples of ERD’s showing the different semantics. I've seen different semantics used so if you are doing coursework, make sure you are using the prescribed technique.
While you might think that the above two models ought to look the same, they can often be quite different. For instance, in an ERD you can often see many-to-many relationships (because at this stage it’s just a conceptual model). But in the physical model, many-to-many relationships have to be “dealt with”. Similarly you may see lots of one-to-one relationships in the ERD because it’s just a thought gathering process but physically you will have these in a single table. So what I’m saying is that the entities in an ERD don’t map exactly to the tables in the physical model. There may be a different number and they may have a subtlely different meaning.
hth
Chris
