I have to design the following sentences for a company that sells different vehicles: "The database must keep track of everyone involved(customer and staff) in the sales for vehicles. The sale price, profit and commission from that profit also needs to be recorded."
I came across many ER diagrams to model such a scenario which involves a ternary relationship between Vehicles, Staff and Customer as can be seen here.(ER1)
And another one where the Sales in actually an Entity? like this.(ER2)
Initially, I was drawing my diagram like this(3) but as it says, the diagram is not accurate and I'm not sure why.
What exactly is the difference between the concept that these two diagrams(ER1 and ER2) explain? It would be a lot of help if someone could explain the difference between the two models and which one is better suited for what I want to record in the database.
If any clarification is needed please let me know.