Storing XML In Database

best way to store questionnaire data in a database.Since different questionnairs have different questions and formats i.e dropdown, radio, checkboxes etc building such a database model becomes highly complex.

I've read that if data schema is complex and higly variable it may be better to use an xml document and store that in a databse. However I dont quite understand how you store xml to a database. Do you simply store the entire structure in something like a nvarchar column or is there some other way to store xml to a database.

If you store the entire structure to the databse then how do you query the content to generate reports.

example xml:

Code:
<survey>
<meta>
<id>sample</id>
</meta>
<questions>
<question id="1" type="singlechoice" page="1">

[code]...