Difference between one-to-many and many-to-one relationship

Question

What is the real difference between one-to-many and many-to-one relationship? It is only reversed, kind of?

I can\'t find any \'good-and-easy-to-understand\' tutoria

Answer 1

One-to-Many and Many-to-One are similar in Multiplicity but not Aspect (i.e. Directionality).

The mapping of Associations between entity classes and the Relationships between tables. There are two categories of Relationships:

1. Multiplicity (ER term: cardinality)
   • One-to-one relationships: Example Husband and Wife
   • One-to-Many relationships: Example Mother and Children
   • Many-to-Many relationships: Example Student and Subject
2. Directionality : Not affect on mapping but makes difference on how we can access data.
   • Uni-directional relationships: A relationship field or property that refers to the other entity.
   • Bi-directional relationships: Each entity has a relationship field or property that refers to the other entity.