Re: PostgreSQL vs SQL/XML Standards

> On 2018-11-9, at 05:07 , Pavel Stehule <pavel.stehule@gmail.com> wrote:
> 
> 
> 
> čt 8. 11. 2018 v 15:18 odesílatel Markus Winand <markus.winand@winand.at <mailto:markus.winand@winand.at>> napsal:
> 
> > On 2018-11-6, at 15:23 , Pavel Stehule <pavel.stehule@gmail.com <mailto:pavel.stehule@gmail.com>> wrote:
> > 
> > 
> > 
> > po 29. 10. 2018 v 11:45 odesílatel Pavel Stehule <pavel.stehule@gmail.com <mailto:pavel.stehule@gmail.com>> napsal:
> > 
> > 
> > po 29. 10. 2018 v 10:11 odesílatel Pavel Stehule <pavel.stehule@gmail.com <mailto:pavel.stehule@gmail.com>> napsal:
> > Hi
> > 
> > čt 25. 10. 2018 v 21:47 odesílatel Alvaro Herrera <alvherre@2ndquadrant.com <mailto:alvherre@2ndquadrant.com>> napsal:
> > On 2018-Oct-25, Pavel Stehule wrote:
> > 
> > > I am thinking so I can fix some issues related to XMLTABLE. Please, send me
> > > more examples and test cases.
> > 
> > Please see Markus Winand's patch that I referenced upthread.
> > 
> > here is a fix of some XMLTABLE mentioned issues.
> > 
> > this update allows cast boolean to numeric types from XPath expressions
> > 
> > Attached patch solves some cast issues mentioned by Chap. It solves issue reported by Markus. I didn't use Markus's code, but it was inspiration for me. I found native solution from libxml2.
> > 
> > Regards
> > 
> > Pavel
> 
> Better than my patch.
> 
> But I think the chunk in xml_xmlnodetoxmltype of my patch is still needed — in one way or the other (see below).
> 
> # select * from xmltable('*' PASSING '<e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>' COLUMNS x XML PATH 'node()');
>                     x
> -----------------------------------------
>  prec1arg&amp;ent1<n2>&amp;deep</n2>post
> (1 row)
> 
> Output is not the original XML.
> 
> I dug a little further and found another case that doesn’t looks right even with my change to xml_xmlnodetoxmltype applied:
> 
> # select * from xmltable('*' PASSING '<e>pre<!--c1--><?pi arg?><![CDATA[&ent1]]><n2>&amp;deep</n2>post</e>' COLUMNS x XML PATH '/');
>              x
> ---------------------------
>  pre&amp;ent1&amp;deeppost
> (1 row)
> 
> Oracle gives in both cases XML.
> 
> To fix that I included XML_DOCUMENT_NODE in the list of nodes that use xmlNodeDump. Now I wonder if that logic should be reversed to use the xmlXPathCastNodeToString branch in a few selected cases but default to the branch xmlNodeDump for all other cases?
> 
> I guess those few cases might be XML_ATTRIBUTE_NODE and XML_TEXT_NODE. Regression tests are happy with that approach but I don’t think that proves a lot.
> 
> -markus
> 
> diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
> index 37d85f7..7c1f884 100644
> --- a/src/backend/utils/adt/xml.c
> +++ b/src/backend/utils/adt/xml.c
> @@ -3682,7 +3682,7 @@ xml_xmlnodetoxmltype(xmlNodePtr cur, PgXmlErrorContext *xmlerrcxt)
>  {
>         xmltype    *result;
> 
> -       if (cur->type == XML_ELEMENT_NODE)
> +       if (cur->type != XML_ATTRIBUTE_NODE && cur->type != XML_TEXT_NODE)
>         {
>                 xmlBufferPtr buf;
>                 xmlNodePtr      cur_copy;
> 
> 
> I used your patch and append regress tests. I checked the result against Oracle.
> 
> Regards
> 
> Pavel

Fine from my side.

-markus