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RE: XML 1.0 - Element order significance
- From: Tim Bray <email@example.com>
- To: Danny Ayers <firstname.lastname@example.org>, email@example.com
- Date: Tue, 23 Jan 2001 10:10:00 -0800
At 10:44 PM 23/01/01 +0600, Danny Ayers wrote:
>If the "document order" is determined by the XML syntax, then I would have
>expected this to appear in the rec.
>Where exactly in the XML spec is "document order" defined?
It is a well-known hole in the XML spec that it never said that
an XML processor is expected to allow software to access elements
in the order of their occurrence - and conversely, is not required
to do so for attributes. The second edition errata made it clear
that attribute order is not significant but did not take the trouble
to make the former point more clear. Probably, nobody felt any
pressure to do this because every piece of XML software in the
universe in fact does this and as far as I know nobody has ever
remotely considered not doing so.
In fact, I've always thought that one of the things that makes
implementing a real native XML data store hard is the fact that you
have to preserve ordering relationships; one of the key principles of
the normalized data models behind RDBMS is that things can be
in whatever order you want; in fact this makes lots of things easier.