Working with the Database - eXist: A NoSQL Database and Application Development Platform - page 99

</exist:result>
</httpclient:body>
</httpclient:response>
The major part of the output is generated by the httpclient:post function. For the
result of our extended query POST request, look at the contents of the
httpclient:body element. Notice that since the request returns a sequence and we
specified a start position and length of 3 , we get the third through fifth elements of
the sequence only.
Extended query request XML format
An extended query request has the following format:
<query xmlns = "http://exist.sourceforge.net/NS/exist"
start? = integer
max? = integer
cache? = "yes" | "no"
session-id? = string >
text
properties?
</query>
• start contains the index (counting from 1) of the first item to be returned.
• max is the maximum number of items to return. Together with start , it allows
you to control which part of the results you'll see.
• Setting cache to yes will have the query start a session. The session ID will be
returned in the result (in the exist:session attribute on the exist:result ele‐
ment) and must be passed in the session-id attribute on subsequent requests.
• session-id allows you to pass a previously created session identifier.
The text element is used to pass the query. You will most likely want to enclose its
contents in a CDATA section ( <text><<![CDATA[ ... ]]></text> ) to avoid XML
parsing errors.
The properties element can be used to set serialization properties like indenting and
character encoding:
<properties>
<property name = string
value = string >*
</properties>
A list of serialization properties can be found in “Serialization Options” on page 119 .