Entity Relationship Diagrams you list the entities and then show either a one to one, one to many, or many to many relationship between them... depending which level ERD you want to do, assuming thats the same as a ERM...
I know what entity relationships are, i did them at uni a couple of years ago. I just want to brush up on it a bit and also relearn Use Case. Was just wondering if anyone could recommend any websites which are any good?