How to model messages exchanged between users? - ER Diagram
<p>I'm trying to design an ER diagram where i have a USER and a MESSAGE entity. Users can send messages to other users. I have designed 2 alternative diagrams for this but i'm not sure which one is the correct. <a href="https://i.stack.imgur.com/PSEyp.png" rel="noreferrer"><img src="https://i.stack.imgur.com/PSEyp.png" alt="In the first one i use a recursive relationship with roles whereas in the second one, i use 2 different relationships."></a></p>