Re: [Exist-open] problem with the evaluation of complex predicates

[Jean-Marc V. <jm...@fr...>]

Were you able to reproduce the bug with a very small dataset ?
Are there many XML levels between tags TEI.2 and letHeading ?

Is there a hint in the log on server side on standard output that .// is 
treated differently from descendant:: ?

Have you tried the XQuery way?

let $streuvels := /TEI.2 [ .//letHeading[author&='streuvels'] ,
     $mijnheer := /TEI.2 [ .//abbr[@expan&='mijnheer']]
return $streuvels intersect $mijnheer


Le 04/06/2004 04:35 PM, Ron Van den Branden a écrit :

> Hi,
>
> There seem to be some problems with the evaluation of queries 
> restrained by complex XPath predicates. I'm quite sure it has nothing 
> to do with my data, rather with the combination of the abbreviated 
> axis specifier './/', and the 'and' and 'or' operators. However, since 
> my data has a more complex structure than the Shakespeare examples, it 
> was more convenient to base my report on these figures.
>
> Initial observations of correct behaviour:
> ==========================================
> I have a collection of 1748 documents
>
> 1) 458 of which have 'streuvels' in the <author> tag:
> /TEI.2[.//letHeading[author&='streuvels']] returns 458 hits
> 2) 96 of which have 'mijnheer' as value for the '@expan' attribute in 
> the <abbr> tag:
> /TEI.2[.//abbr[@expan&='mijnheer']] returns 96 hits
> 3) 7 of which have 'streuvels' in the <author> tag AND 'mijnheer' as 
> value for the '@expan' attribute in the <abbr> tag:
> /TEI.2//letHeading[author&='streuvels'][.//abbr[@expan&='mijnheer']] 
> returns 7 hits

------------[
I think you forgot a [ here before letHeading .

> 4) 547 of which have 'streuvels' in the <author> tag OR 'mijnheer' as 
> value for the '@expan' attribute in the <abbr> tag:
> /TEI.2[.//abbr[@expan&='mijnheer']] | 
> /TEI.2[.//letHeading[author&='streuvels']] returns 547 hits
>
> Where things go wrong:
> ======================
> 5) The intersection of query 3) reformulated as a complex predicate:
>
> /TEI.2[.//letHeading[author&='streuvels'] and 
> .//abbr[@expan&='mijnheer']] returns 458 hits
> /TEI.2[.//abbr[@expan&='mijnheer'] and 
> .//letHeading[author&='streuvels']] returns 96 hits
>
> Seemingly, only the results of the first predicate part are returned.
>
> 6) The union of 4) expressed as a complex predicate:
> /TEI.2[.//abbr[@expan&='mijnheer'] or 
> .//letHeading[author&='streuvels']] returns 1748 hits
>
> Which is the whole of my document set.
>
> When complex predicates behave correctly:
> =========================================
> When in complex predicates the './/' abbreviated axis specifier is 
> replaced by 'descendant::', they return the correct number of results:
>
> 7) intersection:
> /TEI.2[descendant::letHeading[author&='streuvels'] and 
> descendant::abbr[@expan&='mijnheer']] returns 7 hits
> /TEI.2[descendant::abbr[@expan&='mijnheer'] and 
> descendant::letHeading[author&='streuvels']] returns 7 hits
>
> 8) union:
> /TEI.2[descendant::abbr[@expan&='mijnheer'] or 
> descendant::letHeading[author&='streuvels']] returns 547 hits
>
> I've produced these results with the 'basic XQuery Interface' example 
> with eXist-snapshot20040331.
>
> Ron
>

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