title: Group Information for an Id within the same document or Split this to two collections?
body: <p>I am using the Firestore DB with a Flutter application. </p>
  
  <p>In the application, I schedule employees to shifts for the following days.</p>
  
  <p>As a feature, I want to implement a calendar that visualizes employee availability. When an employee is not assigned to a shift or not away he is available. </p>
  
  <p>At the moment I have a collection of <strong>Shifts</strong> and <strong>Employees</strong> within Firebase. I was thinking of creating an <strong>Unavailability</strong> collection but on a second thought that might be unnecessary.</p>
  
  <p>The question is, should I create an <strong>Unavailability</strong> collection within Firebase? Each document would have a property of date, employee name, and reason (employee already assigned, sick, vacation, etc.) Or implement this within the <strong>Employees</strong> collection which already exists. Within this collection, I have stored employee's attributes such as name, salary, email...</p>
  
  <p>My concern with this is that for a given employee document, I will have an attribute with a very long list that contains the unavailability dates. Also, I would like to present the reason for the unavailability. This means I will have to present a shift with its details if the employee is already assigned to a shift or the general unavailability details.</p>
  
  <p>Should I instead implement this within Flutter (3 collections for 1st case)?</p>
  
  <p>Note: If it matters, I am using Bloc for the state management within Flutter.</p>