Testdata mapping question

Hi All,

I am developing a SoapUI test case to test a webservice.
The webservice request looks like below
<library>
<book>
<title>Perl Best Practices</title>
<author>Damian Conway</author>
</book>
<book>
<title>Perl Cookbook, Second Edition</title>
<author>Tom Christiansen</author>
</book>
.............
.........
</library>


I need to submit 100 books in 1 request.
I have the testdata in database and I will be using the datasource to load the test data.
The question is.. How do I retrieve and map 100 request from database to webservice?
what is the best way to implement this solution?
Thanks