[xquery-talk] Re: The State of Native XML databases

[Ilya Sterin]

On 8/20/07, John Snelson <john.snelson at oracle.com> wrote:
> Ilya Sterin wrote:
> >> Some type of schema can of course be useful in different scenarios, but
> >> Ilya's suggestion that "ddl=xml schema" does not suit everyone.
> >
> > Yeah, if you are not looking at XML as a persistence.  You wouldn't
> > work with a relational store without a DDL, be it SQL or any other way
> > to define your schema.  Yes, there are many use cases for using xml in
> > its semi-structured loose format, that's just not for persisting
> > application state per say, rather message snippets, configs, etc...
> > Again, you could also argue that MySQL was useful before InnoDB was
> > introduced.
>
> Unlike the relational data model, XML is (can be) a self descriptive
> format. This is why it is easy to use an XML database without a schema,
> whereas it is impossible with a relational database.
>
> With the XML data model, you have built-in schema evolution
> capabilities. If you impose a schema (XML Schema or otherwise) on your
> XML database, you loose that ability - and have to re-implement it in a
> convoluted way if you need it back again.

I do agree with you in some cases, but as far as schema evolution,
this is where versioning comes in.

>
> John
>