Re: Add XMLNamespaces to XMLElement

Hi

so 21. 12. 2024 v 0:51 odesílatel Jim Jones <jim(dot)jones(at)uni-muenster(dot)de>
napsal:

> Hi,
>
> I'd like to propose the implementation of the XMLNamespaces option for
> XMLElement.
>
> XMLNAMESPACES(nsuri AS nsprefix)
> XMLNAMESPACES(DEFAULT default-nsuri)
> XMLNAMESPACES(NO DEFAULT)
>
> * nsprefix: Namespace's prefix.
> * nsuri: Namespace's URI.
> * DEFAULT default-nsuri: Specifies the DEFAULT namespace to use within
> the scope of a namespace declaration.
> * NO DEFAULT: Specifies that NO DEFAULT namespace is to be
> used within the scope of a namespace declaration.
>
> This basically works pretty much like XMLAttributes, but with a few more
> restrictions (see SQL/XML:2023, 11.2 <XML lexically scoped options>):
>
> * XML namespace declaration shall contain at most one DEFAULT namespace
> declaration item.
> * No namespace prefix shall be equivalent to xml or xmlns.
> * No namespace URI shall be identical to http://www.w3.org/2000/xmlns/
> or to http://www.w3.org/XML/1998/namespace.
> * The value of a namespace URI contained in an regular namespace
> declaration item (no DEFAULT) shall not be a zero-length string.
>
> Examples:
>
> SELECT xmlelement(NAME "foo", xmlnamespaces('http://x.y' AS bar));
> xmlelement
> -------------------------------
> <foo xmlns:bar="http://x.y"/>
>
> SELECT xmlelement(NAME "foo", xmlnamespaces(DEFAULT 'http://x.y'));
> xmlelement
> ---------------------------
> <foo xmlns="http://x.y"/>
>
> SELECT xmlelement(NAME "foo", xmlnamespaces(NO DEFAULT));
> xmlelement
> -----------------
> <foo xmlns=""/>
>
> In transformXmlExpr() it seemed convenient to use the same parameters to
> store the prefixes and URIs as in XMLAttributes (arg_names and
> named_args), but I am still not so sure it is the right approach. Is
> there perhaps a better way?
>
> Any thoughts? Feedback welcome!
>

+1

Pavel

>
> Best, Jim
>