RE: [xml-dev] Results of Open XML balloting at INCITS

["Rick Jelliffe" <rjelliffe@allette.com.au>]

Michael Kay said:
>> I see that Oracle supports XQuery as well as SQL now. What
>> are the clear criteria for someone to use when choosing
>> between W3C XQuery and ISO SQL?
>
> That's like asking how do you choose between email and file transfer.
> Having
> two standards for the same thing is bad; having two standards for
> different
> things is fine, even if there are some applications that could be built
> using either technology.

They are both standard query languages for databases. If you just stopped
there, you might be tempted to say that therefore one was extraneous and
so should not be a standard.

However, it is the details that make the difference. SQL queries
collection of tables and XQuery queries a multi-rooted, ordered, directed
AVG-thingie. Even that might not be enough to say that XQuery had enough
distinction, because it can be implemented on top of SQL (is that still
the way some people do it?)

But it allows different implementation strategies and supports different
kinds of use and users, and comes from a different technical tradition.
There is a different market requirement for it than for SQL, it seems to
me.

Different market requirement, different use and users, different
implementation strategies, different technical tradition, different data
model => different standard.

That two technologies can be described by the same simple sentence is not
evidence that it would not be useful for both to be standards.

Cheers
Rick Jelliffe