title: Why we use NLS_INSTANCE_PARAMETER?
body: <p>For eg :</p>
  
  <pre><code>Select * from nls_instance_parameter
  where parameter = 'NLS_DATE_FORMAT';
  
  PARAMETER               VALUE
  NLS_DATE_FORMAT         DD-MON-RR
  </code></pre>
  
  <p>Can anyone explain when to use NLS_INSTANCE_PARAMETER ? and What is NLS_INSTANCE_PARAMETER ?</p>