Re: XMLDocument (SQL/XML X030)

Hi

On 24.01.25 07:28, Pavel Stehule wrote:
> I think documentation should be strongly enhanced. This is probably
> the hardest part of this patch - explain well what this function does
> and what it doesn't.

You mean something like this? Or perhaps something more technical?

The <function>xmldocument</function> function returns a document node,
representing an XML document, from the provided <type>xml</type>
expression. The input expression can represent any valid XML content,
including elements, text, or a sequence of nodes. If the
<type>xml</type> expression is NULL, the function returns NULL. This
function does not require the input to have a single root node or
encapsulate the result in a root element. The validation of the
<type>xml</type> expression depends on the current <xref
linkend="guc-xmloption"/> setting.

Example:

WITH xmldata (val) AS (
  VALUES
    (xmlparse(DOCUMENT '<root><foo>bar</foo></root>')),
    (xmltext('foo&bar')),
    (xmlelement(NAME el)),
    (xmlforest(42 AS foo, 73 AS bar))
)
SELECT xmldocument(val) FROM xmldata;

         xmldocument
-----------------------------
 <root><foo>bar</foo></root>
 foo&amp;bar
 <el/>
 <foo>42</foo><bar>73</bar>
(4 rows)

Thanks!

Best, Jim