Re: Re: From TODO, XML?

Bruce Momjian wrote:
>
> > > I would find it very helpful to see a table of what sorts of XML
> > > functionality each major vendor supports.
> >
> > Actually I was thinking of databases of data, not database systems.
>
> I think we can go two ways. Allow COPY/pg_dump to read/write XML, or
> write some perl scripts to convert XML to/from our pg_dump format. The
> latter seems quite easy and fast.

I have been fighting, for a while now, with idiot data vendors that think XML
is a cure all. The problem is that XML is a hierarchical format where as SQL is
a relational format.

It would be good to get pg_dump to write an XML file and DTD, but getting
external sources of XML into PostgreSQL is WAY more complicated. If an XML
import is to be useful beyond just a different format for pg_dump, there has to
be some intelligent database construction based on the XML information.

Go to mp3.com, and download some of their XML format data, first, it is bad
XML, second, it is hierarchical.

I have managed to get several XML files into PostgreSQL by writing a parser,
and it is a huge hassle, the public parsers are too picky. I am thinking that a
fuzzy parser, combined with some intelligence and an XML DTD reader, could make
a very cool utility, one which I have not been able to find.

Perhaps it is a two stage process? First pass creates a schema which can be
modified/corrected, the second pass loads the data.