Re: [DOCS] New XML section for documentation

Peter Eisentraut wrote:
> Bruce Momjian wrote:
> > XML Document Support
> > ====================
> > XML support is not one capability, but a variety of features
> > supported by a database.
>
> database system

Done.

> > Storage
> > -------
> > PostgreSQL stores XML documents as ordinary text documents.
>
> It is "possible" to do that, but this sounds like it's done
> automatically or implicitly.  Maybe:
>
> "PostgreSQL does not have a specialized XML data type.  The recommended
> way is to store XML documents as text."

Clarified.

> > Import/Export
> > -------------
> > Because XML documents are stored as normal text documents, they can
> > be imported/exported with little complexity.
>
> Import/export refers to exporting schema data with XML decorations.  Of
> course you can export column data trivially, but that's not what this
> is about.

OK, section redone.

> > Validation
> > ----------
> > /contrib/xml2 has a function called xml_valid() that can be used in
> > a CHECK constraint to enforce that a field contains valid XML.  It
> > does not support validation against a specific XML schema.
>
> Then this is not validation but only checking for well-formedness.  The
> xml2 README says so, in fact.

I made it clear in the section that the XML syntax was being checked,
not validation against a schema.  You want Check and Validation
sections?

> > Indexing
> > --------
>
> I think the expression index capability combined with contrib/xml2 is
> more relevant here than the full-text search capability.

Agreed, added.

> > Transforming
> > ------------
> > /contrib/xml2 supports XSL transformations.
>
> That's XSLT.

OK.

> > XML to SQL Mapping
> > -------------------
> > This involves converting XML data to and from relational structures.
> > PostgreSQL has no internal support for such mapping, and relies on
> > external tools to do such conversions.
>
> Are there instances of such tools?

Well, it seems EMS has a product that does it, and I assume other XML
tools have database interfaces.  Also, psql can do it if you want to
convert XHTML to XML, so I mentioned that too.

--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

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