title: ER diagram: Total participation and weak entities
body: <p>So, in this semester I started learning about DBMS and the first two chapters was about ER systems. But even though i understand what is a weak entity and the definition of total participation I find it hard to distinguish what to use in practice..For example</p>
  
  <p><a href="https://i.stack.imgur.com/Uiuuk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Uiuuk.png" alt="enter image description here"></a></p>
  
  <p>In this simple example I cant understand why the restaurant is not a weak entity (It cant exist a restaurant without dishes) and the same for dish-ingredients (it can not exist a dish with 0 ingredients). So, why in this diagram restaurant -dish and dish-ingrendient are only represented with a total participation and not as a weak entities too? </p>