Import data from XML file

Hi!

How do you import data from an xml-file?
For instance, if I have a file like this:

<?xml version="1.0" encoding="utf-8"?>
 <p_update>
   <main_categories>
     <main_category>
       <main_category_name>Sonstiges</main_category_name>
       <main_category_id>5</main_category_id>
     </main_category>
     <main_category>
       <main_category_name>Buehne</main_category_name>
      <main_category_id>2</main_category_id>
    </main_category>
    <main_category>
      <main_category_name>Konzerte</main_category_name>
      <main_category_id>1</main_category_id>
    </main_category>
  </main_categories>
  <categories>
    <category>
      <category_name>Reggae</category_name>
      <main_category_id>1</main_category_id>
      <category_id>45</category_id>
    </category>
    <category>
      <category_name>sonstige</category_name>
      <main_category_id>5</main_category_id>
      <category_id>44</category_id>
    </category>
</categories>
</p_update>


... and I want a CSV file like this:

main_category_name    main_category_id
Sonstiges    5
Buehne    2

category_name    main_category_id   category_id
Reggae    1    45
sonstige    5    44


Or is there a way to import directly into tables in a postgres
database?


Your help would be appreciated!
Regards
Erwin