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