Crow's foot notation
erDiagram
CUSTOMER ||--o{ ORDER : "places / placed by"
ORDER ||--|{ ORDER_ITEM : "contains / belongs to"
PRODUCT ||--o{ ORDER_ITEM : "included in / includes"
PERSON ||--|{ ROUTE : "assigned to / assigned by"
CUSTOMER }o--|| ROUTE : "belongs to / covers"
ORDER_ITEM ||--o{ DELIVERY : "fulfilled by / fulfils"