Use of Entity or Relationship Sets
It is not always clear whether an object is best represented by an entity set or a relationship set.
- Figure shows how we might model an account as a relationship between a customer and a branch.
Figure : E-R diagram with account as a relationship set
- This new representation cannot model adequately the situation where customers may have joint accounts. (Why not?)
- If every account is held by only one customer, this method works.