title: How to make an SSD out of a Use Case with only 1 class in the Domain Model?
body: <p>As a project in college, we have to make an application. It is made using Agile. We build the application Use Case (Refered to as UC) by Use Case, from analysis to design and the programming. The first UC is logging in. However, we are having quite a lot of trouble and our professor simply tells us to figure it out ourselves and Google is our best friend. </p>
  
  <p>The Use Case: post-condition is 'user is logged in'.</p>
  
  <blockquote>
    <p>1: User wants to log in.</p>
    
    <p>2: System asks username and password.</p>
    
    <p>3: User gives username and password.</p>
    
    <p>4: System validates using a database.</p>
    
    <p>5: System shows username.</p>
    
    <p>6: System shows a menu (link to further UC's)</p>
  </blockquote>
  
  <p>From this Use Case alone, we have to make a first iteration. We make a domain model, System Sequence Diagram, Operation Contract if possible, Sequence Diagram and Design Class Diagram.</p>
  
  <p>From this information alone, we only have 1 class in our domain model (player with attributes 'username' and 'password'.
  Is it possible to make a System Sequence Diagram out of this or should we have at least 2 classes?</p>
  
  <p>This is literally our first application and we haven't seen anything about database integration yet.</p>
  
  <p>SSD: https://imgur.com/a/Yi7g9">SSD
  'Speler' translates to 'player', 'geefGegevens' translate to 'supplyData' (not a direct translaton, the user supplies username and password)</p>