title: Why does SQL server have both server and database layer authentication (Login and User) but Oracle only has user one's?
body: <p>SQL Server uses server authentication for accessing servers, and user authentication for accessing different database, but Oracle does the same thing using only user authentication</p>
  
  <p>My question is , why MS use double layer authentication for accessing a database. Is there any real benefit for it compared to Oracle user authentication? Or vice versa</p>