Modifying XML Stored in a CLOB

Question

I've got XML documents stored in a column using the CLOB datatype on a 10gR2 database.
We once tried to use the XML type, but there was a 64k size limit I think (can't recall the specifics, maybe that limitation has since been fixed). Do you happen to know?
My problem is that now I need to write a script to modify the format of the date found between the <date-created> </date-created> XML tags within each CLOB.
For example <date-created>2007-01-01 00:00:00</date-created> would become <date-created>01-01-2007 00:00:00</date-created>.
I can certainly figure out how to parse the XML and do an UPDATE to each row through a PL/SQL script, but before I go down that road I thought I'd ask if there are any tools that might make this task easier for me? I have thousands of entries that need modified, so it must be an automated process.
For example, maybe there are some PL/SQL procedures for manipulating CLOB data?
I figure it doesn't hurt to ask before I start this task if there's an easy way to go about this or if anyone else has had a similar problem to solve and could share the code they used.
Thank you

Answer 1

it's YYYY-MM-DD and other rows (the newer ones) have the format MM-DD-YYYYOk, i thought you're changing the date format for all the rows and hence i was wondering if looping through each row is required or not. Anyway, i still think you can filter out all the rows with the older format, and just use a single update statement to update the xml node values for those.
hr@XE> create table myxml(id number, xmlcol xmltype);
Table created.
hr@XE> insert into myxml values(1, '<root> <date1> 01-04-2007 </date1> </root>');
1 row created.
hr@XE> insert into myxml values(2, '<root> <date1> 11-04-2007 </date1> </root>');
1 row created.
hr@XE> update myxml
set xmlcol = updatexml(xmlcol,'/root/date1/text()',
to_char(to_date(extractvalue(xmlcol,'/root/date1'),'DD-MM-YYYY'),'mm/dd/yyyy')    );
2 row updated.
hr@XE>  select id, xmlcol from myxml;
        ID
XMLCOL
         1
<root>
  <date1>04/01/2007</date1>
</root>
         2
<root>
  <date1>04/11/2007</date1>
</root>