Personally I'd try to parse the XML record by record (for example using XML::Twig, allegedly — I never could wrap my head around that module, so I wrote my own), put it into a perl hash, and convert the hash into SQL using SQL::Abstract. With DBIx::Simple you can use the SQL::Abstract syntax to put the data straight into the database.

while(my $row = read_row_from_xml($input)) {
    $db->insert(mytable  => $row);
}
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$row is suppoed to look something like

{
    'foo' => 123,
    'bar' => 456,
    'comment' => 'This is plain text',  # NOT escaped
    'undefined' => undef,               # becomes NULL
}
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Writing the sub read_row_from_xml is left as an exercise for the user.