Mailorder database:
Tablename
 field1  | field2  |...
 one example row

Customers
| cno  | cname   | street       | zip   | phone        |
+------+---------+--------------+-------+--------------+
| 1111 | Charles | 123 Main St. | 67226 | 316-636-5555 |

Orders
| ono  | cno  | eno  | received   | shipped    |
+------+------+------+------------+------------+
| 1020 | 1111 | 1000 | 1994-12-10 | 1994-12-12 |

Zipcodes
| zip   | city    |
+-------+---------+
| 67226 | Wichita |

Employees
| eno  | ename | zip   | hdate      |
+------+-------+-------+------------+
| 1000 | Jones | 67226 | 1995-12-12 |

Odetails
| ono  | pno   | qty  |
+------+-------+------+
| 1020 | 10506 |    1 |

Parts
| pno   | pname              | qoh  | price | olevel |
+-------+--------------------+------+-------+--------+
| 10506 | Land Before Time I |  200 | 19.99 |     20 |


What should the primary and foreign keys be?
Draw a ERD diagram.