title: What would be the cardinality of Employee and Department?
body: <blockquote>
    <p>A company database needs to store information about employees
    (identified by ssn, with salary and phone as attributes), </p>
    
    <p>departments (identified by dno, with dname and budget as attributes),
    and children of employees (with name and age as attributes). </p>
    
    <p>Employees work in departments; each department is managed by an
    employee; </p>
    
    <p>a child must be identified uniquely by name when the parent (who is an
    employee; assume that only one parent works for the company) is known.</p>
    
    <p>We are not interested in information about a child once the parent
    leaves the company.</p>
    
    <p>Draw an ER diagram that captures this information.</p>
  </blockquote>
  
  <p><a href="https://i.stack.imgur.com/ezkKy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ezkKy.png" alt="enter image description here"></a></p>
  
  <p>I am using "Look Across" Min-Max notation here.</p>
  
  <p>Are the cardinalities between Employee and Department correct?</p>
  
  <p>For instance, is it possible that a Department has zero Employees? Or, is this a relevant information?</p>