title: Should this ER diagram use a ternary relationship instead
body: <p>I've been looking at examples of ER diagrams to better understand them. I came across an ER diagram that I am not sure is correct. </p>
  
  <p>Here is the question/specification: </p>
  
  <blockquote>
    <p>UPS prides itself on having up-to-date information on the processing and current location of each
    shipped item. To do this, UPS relies on a company-wide information system. Shipped items are
    the heart of the UPS product tracking information system. Shipped items can be characterized
    by item number (unique), weight, dimensions, insurance amount, destination, and final delivery
    date. Shipped items are received into the UPS system at a single retail center. Retail centers are
    characterized by their type, uniqueID, and address. Shipped items make their way to their
    destination via one or more standard UPS transportation events (i.e., flights, truck deliveries).
    These transportation events are characterized by a unique scheduleNumber, a type (e.g., flight,
    truck), and a deliveryRoute. </p>
  </blockquote>
  
  <p>Entities: <code>RetailCenter</code>, <code>ShippedItems</code>, <code>Transportation Event</code><br>
  Relationships: <code>ReceivedFrom(RetailCenter,ShippedItems)</code>, <code>ShippedVia(ShippedItems,TransportationEvent)</code></p>
  
  <p>Here is the diagram: <a href="https://i.stack.imgur.com/Duuir.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Duuir.png" alt="er diagram"></a></p>
  
  <p>My questions is that shouldn't there be a ternary relationship between the three entities? My thought process is that a shipped item takes a transportation event to reach a specific retail center. Doesn't this diagram say that a shipped item is received by a retail center and that a shipped item takes a transportation event?</p>