There are basically three different kinds of relationships which are -
Dependencies - They are the relationship between two different entities. If any single entity is changed then the impact would be laid on the other too. It also depicts that one class use another class as an argument in the signature of the operation.
Generalization - In this relationship, the specified class and subclass ratio is evaluated. It also depicts that one entity inherits the properties of the other entity.
Association - Association is a structural relationship between two different objects.