[xquery-talk] Is there any point of using xml:id with an xml db?

James Fuller james.fuller.2007 at gmail.com
Thu May 5 05:54:42 PDT 2011


On Thu, May 5, 2011 at 2:44 PM, Andrew Welch <andrew.j.welch at gmail.com> wrote:
> Hi,
>
> Is there any benefit to using xml:id with an xml database, over a
> plain old id attribute with a range index?  (lookup performance rather
> than uniqueness checking)

lookup will be faster

> Out of interest, if you did use xml:id and then create a range index
> for that, which would get used?

I would hope that a database would rewrite id() expressions to use a
built-in index ... will check around to see what xml databases
actually do.

J

ps: John Snelson, if you are listening this is probably a good
candidate rule for your optimization rewrites ala
http://www.xmlprague.cz/2011/sessions.html#Declarative-XQuery-Rewrites-for-Profit-or-Pleasure



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