title: Why is a "GRANT USAGE" created the first time I grant a user privileges?
body: <p>I'm new to the admin side of DBMS and was setting up a new database tonight (using MySQL) when I noticed this. After granting a user a privilege for the first time, another grant is created that looks like</p>
  
  <pre><code>GRANT USAGE on *.* TO user IDENTIFIED BY PASSWORD password
  </code></pre>
  
  <p>The documentation says that the <code>USAGE</code> privilege means "no privileges," so I'm inferring thats grants work hierarchically and perhaps a user must have some kind of privilege for all databases, so this serves as a catch all? </p>
  
  <p>I also dont understand why this line has an <code>IDENTIFIED BY</code> clause in it when the grant I created does not have one (mostly because I dont understand what purpose the <code>IDENTIFIED BY</code> clause serves).</p>
  
  <p><em>Edit:</em> Sorry for not stating this originally, the grants were</p>
  
  <pre><code>GRANT ALL PRIVILEGES ON database.* TO admin_user
  GRANT SELECT, INSERT, UPDATE, DELETE ON database.* TO user
  </code></pre>