For each of the following pairs of rules, identify two entity types and one relationship. State the cardinality and existence of the relationship in each case. If you don't think enough information is available to define either of these, then state an assumption that makes it clear. Draw the ER diagram.

1. A department employs many persons. A person is employed by, at most, one department.

2. A manager manages, at most, one department. A department is managed by, at most, one manager.

3. An author may write many books. A book may be written by many authors.

4. A team consists of many players. A player plays for only one team.

5. A lecturer teaches, at most, one course. A course is taught by exactly one lecturer.

6. A flight-leg connects two airports. An airport is used by many flight-legs.

7. A purchase order may be for many products. A product may appear on many purchase orders.

8. A customer may submit many orders. An order is for exactly one customer.