Looping through XML Items

Question

Hi,
I am selecting data from tables in forms of xml like below
xml_data VARCHAR2(32000) :=
SELECT XMLELEMENT("form",
xmlagg(xmlelement("item",
XMLFOREST(form_seq_no "form_seq_no",
patientid "patientid",
facilityid "facilityid"
from (SELECT
e.form_seq_no,
e.patientid,
e.facilityid
FROM hosp e
I am using a cursor like below to get the data
OPEN l_rc FOR xml_data;
LOOP
if l_rc%notfound then
EXIT ;
end if;
FETCH l_rc
INTO l_xml;
update hosp set transmit_date = sysdate;
end loop;
CLOSE l_rc;
The above query returns all items in the table....I am trying to limit the number of records returned based on limit I pass...If the user enters 2, only two items from the node has to be returned. I am not having a clue on how to do this. It would be great if any one can help me...

Answer 1

Thank you both for the replies. I am able to get the data based on the limit I pass...I have another question.
Once the xml doc result is returned or once the select operation is performed and cursor data is fetched into a xmltype variable, I am updating a table's data with the current date...But I have to update the table based on the form_seq_no in the result xml doc...If the result set has three records, then it would have three different form_seq_no. Right now I am doing like below
SELECT XMLELEMENT("form",
xmlagg(xmlelement("item",
XMLFOREST(form_seq_no "form_seq_no",
patientid AS "patientid",
facilityid AS "facilityid" ))))
INTO l_xml
from (SELECT
e.form_seq_no,
e.patientid,
e.facilityid
FROM hosp e
ORDER BY e.form_seq_no
WHERE ROWNUM < p_num_of_rows;
I am using a cursor like below to get the data
OPEN l_rc FOR xml_data;
LOOP
if l_rc%notfound then
EXIT ;
end if;
FETCH l_rc
INTO l_xml;
This is the update I am doing, based on the result set I pasted below....But I get an error that extractValue can return only one child...I am at loss to know how to loop through the result set and perform the update...
update hosp set transmit_date = sysdate where form_seq_no = extractValues(l_xml, 'form/item/form_seq_no);
end loop;
CLOSE l_rc;
If I give rownum <3 , I get 3 rows, the result set might look like as follows:
<form>
<item>
<form_seq_no>1</form_inst_seq_no>
<patientid>21</patientid>
<facilityid>23</facilityid>
</item>
<item>
<form_seq_no>2</form_inst_seq_no>
<patientid>212</patientid>
<facilityid>233</facilityid>
</item>
<item>
<form_seq_no>3</form_inst_seq_no>
<patientid>213</patientid>
<facilityid>234</facilityid>
</item>
I am new to this xml and xml manipulation in oracle...What are the concepts I would have to know in order to achieve my task above? And Right now I have this book called "Oracle Database 11g The Complete Reference" by Kevin Loney, but I neither find any elaborate explanations nor examples. What other books would anyone suggest to learn more on oracle and pl/sql.
Thanks a lot in advance.