title: Correct use of signals in an activity diagram
body: <p>I have a question regarding activity diagrams. I read a lot of materials on the topic but to be honest, I am still not sure about the signal sending and receiving.</p>
  
  <p>I did a simple activity diagram for the password authentication.</p>
  
  <p>Basically what I want to do is to send a message to the client after the server performs a search in the database. Is this use of signals correct?</p>
  
  <p>Any criticism toward the structure of the diagram will be welcomed. </p>
  
  <p>Here is the mentioned diagram:</p>
  
  <p><img src="https://i.stack.imgur.com/aY1VE.png" alt=""></p>