title: How to create identifier_hash in typo3's sys_file?
body: <p>I want to import some files in Typo3 system using external php Script. How do I create hash field value like <code>identifier_hash</code> <code>folder_hash</code> <code>sha1</code> for <strong>sys_file</strong> table? </p>
  
  <p>If I leave these fields empty there is error: </p>
  
  <pre><code>Attempt to modify record '3094' (sys_file_reference:3094) without permission. Or non-existing page.
  </code></pre>