Attributes of Relationship types

A relationship type can have attributes:
For example, HoursPerWeek of WORKS_ON
Its value for each relationship instance describes the number of hours per week that
an EMPLOYEE works on a PROJECT.
A value of HoursPerWeek depends on a particular (employee, project) combination
Most relationship attributes are used with M:N relationships.
In 1:N relationships, they can be transferred to the entity type on the N-side of the