title: Refreshing an existing materialized View
body: <p>I created a materialized view with the following information.</p>
  
  <pre><code>CREATE MATERIALIZED VIEW EMPLOYEE_INFO
  AS
  SELECT * FROM EMPLOYEE_TABLE WHERE LOCATION = 'Brazil'
  </code></pre>
  
  <p>I did not add any refresh interval to this MV initially. Now, I need to refresh this MV everyday at 0000HRS.
  Will the following command help me to alter it for everyday at 0000HRS?</p>
  
  <pre><code>ALTER MATERIALIZED VIEW EMPLOYEE_INFO
  REFRESH COMPLETE 
  START WITH SYSDATE
  </code></pre>
  
  <p>In case, I need to refresh it for every 6 hours, how do I perform it? Is it possible?</p>