Dear Nuria,
Am 18.02.2013 16:39, schrieb Nuria Garcia:
> Thanks for your quick answer.
sorry for taking so long this time...
> One more question, in a similar query but with attributes, it looks like the
> index doesn´t get applied (more similar to our real situation):
> Compiling:
> - rewriting where clause to predicate(s)
> - pre-evaluating db:open("bbdd_1")
> - simplifying descendant-or-self step(s)
> - converting descendant::*:businessEvent to child steps
> - pre-evaluating db:open("bbdd_2")
> - simplifying descendant-or-self step(s)
> - simplifying descendant-or-self step(s)
> - swapping operands: descendant::*:inputs/.../fn:data(@*:element) =
> $col1/descendant::inputs/.../fn:data(@element)
> - simplifying descendant-or-self step(s)
> - converting descendant::*:businessEvent[...] to child steps
> - simplifying descendant-or-self step(s)
> Is it possible that the index doesn’t get applied?, how could I improve this
> query?
Yes, the index is not applied, otherwise there would be the line
"applying attribute index" in the compilation info. That is because of
the calls to `fn:data()` around the attribute steps in the `where`
clause. These are unnecessary and hide the attribute comparisons from
the optimizer. Removing them triggers the optimization in my tests.
Hope that helps,
cheers, Leo
BTW: The XML example you posted looks quite "enterprisey" and ignores
quite some XML best-practices. Its structure could easily confuse the
query optimizer because of all the attribute/text comparisons. If you
have any influence on the structure of your data, it would probably be
beneficial to encode the `@name` attributes as element names, which are
currently all the same anyways. The result could look something like this:
<data>
<id>229388252</id>
<matriculation>2751 XTE</matriculation>
<clientId>XTETVTTJKC</clientId>
<driver>
<name>driver name</name>
<surname>driver surname</surname>
<nif>21973887X</nif>
<line1>line 1</line1>
<line2>Line 2</line2>
<city>City name</city>
<cp>28197</cp>
<region>Region7</region>
<country>Country</country>
</driver>
<accident>
<date>
<year>2012</year>
<month>13</month>
<day>22</day>
<hour>2</hour>
<minute>53</minute>
</date>
<address>
<line1>Avenue 5</line1>
<line2>Line2</line2>
<city>Madrid</city>
<cp>28224</cp>
<region>Region3</region>
<country>Spain</country>
</address>
<declaration>Lorem ipsum dolor ....</declaration>
</accident>
</data>
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