For each of the following pairs of enterprise rules, identify two entity types and one relationship type. State the degree of the relationship in each case.
(a) A department employs many persons. A person is employed by, at most, one department.
(b) A manager manages, at most, one department. A department is managed by, at most, one manager.
(c) An author may write many books. A book may be written by many authors.
(d) A team consists of many players. A player plays for only one team.
(e) A lecturer teaches, at most, one course. A course is taught by exactly one lecturer.
(f) A flight-leg connects two airports. An airport is used by many flight-legs.
(g) A purchase-order may be for many products. A product may appear on many purchase-orders.
(h) A customer may submit many orders. An order is for exactly one customer.