XQuery fold-left Problem
Tuesday, 19 December 2023 · 5 messages
ML
Marco Duiker - LandGoed19 Dec 2023 09:53 #
Please help me with the following problem:
I try to construct the current status of a series of objects along the following simple rules:
* the current status of on object with a certain
identificatie (id) is the newest version of that object
* except when the newest object has the property
<status>beëindigen</status> then the object stops existing.
I use a fold-left to proces these rules with a simple function implementing those rules. This gives me unexpected results.
I've reduced the problem to a single stand alone query in which the last object (obj3) has the property <status>beëindigen</status>.
So I would expect this line:
let $stand4 := fold-left(($obj3, $obj2, $obj1), (), function($stand, $obj) { local:stand-totaal($stand, $obj) })
to give me an empty result as `obj3`has the property
<status>beëindigen</status>
but I am getting obj1 as demonstrated in the following stand alone query.
When running the stand alone query I would *expect*:
2 <-> 1 as shown in the result (obj2)
3 <-> 1 as shown in the result (empty as `obj3`has the property <status>beëindigen</status>)
3 <-> 2 as shown in the result (empty as `obj3`has the property <status>beëindigen</status>)
3 <-> 2 <-> 1 as 3 <-> 2 and 3 <-> 1 (empty as obj3 has the property <status>beëindigen</status>) *but in the result I am getting *obj1.
What am I doing wrong?
Any help greatly appreciated.
The query I use:declare namespace op="http://www.geostandaarden.nl/imow/opobject";
declare namespace
da="http://www.geostandaarden.nl/imow/datatypenalgemeen";
declare namespace
ga="http://www.geostandaarden.nl/imow/gebiedsaanwijzing";
declare namespace gml="http://www.opengis.net/gml/3.2";
declare namespace l="http://www.geostandaarden.nl/imow/locatie";
declare namespace ow="http://www.geostandaarden.nl/imow/owobject";
declare namespace
ow-dc="http://www.geostandaarden.nl/imow/bestanden/deelbestand";
declare namespace r="http://www.geostandaarden.nl/imow/regels" ;
declare namespace
rol="http://www.geostandaarden.nl/imow/regelsoplocatie" ;
declare namespace
sl="http://www.geostandaarden.nl/bestanden-ow/standlevering-generiek" ;
declare namespace xlink="http://www.w3.org/1999/xlink" ;
declare namespace xsi="http://www.w3.org/2001/XMLSchema-instance";
declare namespace
rg="http://www.geostandaarden.nl/imow/regelingsgebied";
declare function local:id
(: returns the id(s) of ow-object(s) :)
($seq as item()*) as item()* {
$seq//*:owObject/*/*:identificatie | $seq/*/*:identificatie
};
declare function local:stand-totaal
(: returns an object by comparing new to old :)
(: newest should be returned, except when
<ow:status>beëindigen</ow:status>
then no object should be returned :)
($new as item()*,
$old as item()*) as item()* {
let $new_ids := local:id($new)
let $stand_deel1 :=
for $obj_oud in $old//*:owObject
where not(local:id($obj_oud) = $new_ids)
return <sl:stand>{ $obj_oud }</sl:stand>
let $stand_deel2 :=
for $obj_new in $new//*:owObject[not(.//*:status)]
return <sl:stand>{ $obj_new }</sl:stand>
return ($stand_deel1, $stand_deel2)
};
let $obj1 := <sl:stand>
<ow-dc:owObject
xmlns:ow-dc="http://www.geostandaarden.nl/imow/bestanden/deelbestand"
xmlns:sl="http://www.geostandaarden.nl/bestanden-ow/standlevering-generiek"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<r:RegelVoorIedereen
xmlns:r="http://www.geostandaarden.nl/imow/regels">
<r:identificatie>nl.imow-mnre1034.juridischeregel.OR0000000027</r:identificatie>
<r:idealisatie>http://standaarden.omgevingswet.overheid.nl/idealisatie/id/concept/Exact</r:idealisatie>
<r:artikelOfLid>
<r:RegeltekstRef xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.regeltekst.OR0000000027"/>
</r:artikelOfLid>
<r:thema>http://standaarden.omgevingswet.overheid.nl/thema/id/concept/WaterEnWatersystemen</r:thema>
<r:locatieaanduiding>
<l:LocatieRef
xmlns:l="http://www.geostandaarden.nl/imow/locatie"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.ambtsgebied.LND6030B"/>
</r:locatieaanduiding>
</r:RegelVoorIedereen>
</ow-dc:owObject></sl:stand>
let $obj2 := <sl:stand>
<ow-dc:owObject
xmlns:ow-dc="http://www.geostandaarden.nl/imow/bestanden/deelbestand"
xmlns:sl="http://www.geostandaarden.nl/bestanden-ow/standlevering-generiek"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<r:Instructieregel xmlns:r="http://www.geostandaarden.nl/imow/regels">
<r:identificatie>nl.imow-mnre1034.juridischeregel.OR0000000027</r:identificatie>
<r:idealisatie>http://standaarden.omgevingswet.overheid.nl/idealisatie/id/concept/Exact</r:idealisatie>
<r:artikelOfLid>
<r:RegeltekstRef xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.regeltekst.OR0000000027"/>
</r:artikelOfLid>
<r:thema>http://standaarden.omgevingswet.overheid.nl/thema/id/concept/WaterEnWatersystemen</r:thema>
<r:locatieaanduiding>
<l:LocatieRef
xmlns:l="http://www.geostandaarden.nl/imow/locatie"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.gebied.Kustfundament"/>
</r:locatieaanduiding>
<r:gebiedsaanwijzing>
<ga:GebiedsaanwijzingRef
xmlns:ga="http://www.geostandaarden.nl/imow/gebiedsaanwijzing"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.gebiedsaanwijzing.Kustfundament"/>
<ga:GebiedsaanwijzingRef
xmlns:ga="http://www.geostandaarden.nl/imow/gebiedsaanwijzing"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.gebiedsaanwijzing.RGKustfundament"/>
</r:gebiedsaanwijzing>
<r:instructieregelInstrument>http://standaarden.omgevingswet.overheid.nl/instrument/id/concept/Omgevingsplan</r:instructieregelInstrument>
</r:Instructieregel>
</ow-dc:owObject></sl:stand>
let $obj3 := <sl:stand>
<ow-dc:owObject
xmlns:ow-dc="http://www.geostandaarden.nl/imow/bestanden/deelbestand"
xmlns:sl="http://www.geostandaarden.nl/bestanden-ow/standlevering-generiek"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<r:Instructieregel xmlns:r="http://www.geostandaarden.nl/imow/regels">
<ow:status
xmlns:ow="http://www.geostandaarden.nl/imow/owobject">beëindigen</ow:status>
<r:identificatie>nl.imow-mnre1034.juridischeregel.OR0000000027</r:identificatie>
<r:idealisatie>http://standaarden.omgevingswet.overheid.nl/idealisatie/id/concept/Exact</r:idealisatie>
<r:artikelOfLid>
<r:RegeltekstRef xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.regeltekst.OR0000000027"/>
</r:artikelOfLid>
<r:thema>http://standaarden.omgevingswet.overheid.nl/thema/id/concept/WaterEnWatersystemen</r:thema>
<r:locatieaanduiding>
<l:LocatieRef
xmlns:l="http://www.geostandaarden.nl/imow/locatie"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.gebied.Kustfundament"/>
</r:locatieaanduiding>
<r:gebiedsaanwijzing>
<ga:GebiedsaanwijzingRef
xmlns:ga="http://www.geostandaarden.nl/imow/gebiedsaanwijzing"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.gebiedsaanwijzing.Kustfundament"/>
<ga:GebiedsaanwijzingRef
xmlns:ga="http://www.geostandaarden.nl/imow/gebiedsaanwijzing"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.gebiedsaanwijzing.RGKustfundament"/>
</r:gebiedsaanwijzing>
<r:instructieregelInstrument>http://standaarden.omgevingswet.overheid.nl/instrument/id/concept/Omgevingsplan</r:instructieregelInstrument>
</r:Instructieregel>
</ow-dc:owObject></sl:stand>
let $stand1 := fold-left(($obj2, $obj1), (), function($stand, $obj)
{ local:stand-totaal($stand, $obj) })
let $stand2 := fold-left(($obj3, $obj1), (), function($stand, $obj)
{ local:stand-totaal($stand, $obj) })
let $stand3 := fold-left(($obj3, $obj2), (), function($stand, $obj)
{ local:stand-totaal($stand, $obj) })
let $stand4 := fold-left(($obj3, $obj2, $obj1), (),
function($stand, $obj) { local:stand-totaal($stand, $obj) })
return ( '2 <-> 1 ==================', $stand1,
'3 <-> 1 ==================', $stand2,
'3 <-> 2 ==================', $stand3,
'3 <-> 2 <-> 1 ============', $stand4
)The results:
2 <-> 1 ==================
<sl:stand
xmlns:sl="http://www.geostandaarden.nl/bestanden-ow/standlevering-generiek">
<ow-dc:owObject
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:ow-dc="http://www.geostandaarden.nl/imow/bestanden/deelbestand">
<r:Instructieregel
xmlns:r="http://www.geostandaarden.nl/imow/regels">
<r:identificatie>nl.imow-mnre1034.juridischeregel.OR0000000027</r:identificatie>
<r:idealisatie>http://standaarden.omgevingswet.overheid.nl/idealisatie/id/concept/Exact</r:idealisatie>
<r:artikelOfLid>
<r:RegeltekstRef xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.regeltekst.OR0000000027"/>
</r:artikelOfLid>
<r:thema>http://standaarden.omgevingswet.overheid.nl/thema/id/concept/WaterEnWatersystemen</r:thema>
<r:locatieaanduiding>
<l:LocatieRef xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:l="http://www.geostandaarden.nl/imow/locatie"
xlink:href="nl.imow-mnre1034.gebied.Kustfundament"/>
</r:locatieaanduiding>
<r:gebiedsaanwijzing>
<ga:GebiedsaanwijzingRef
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:ga="http://www.geostandaarden.nl/imow/gebiedsaanwijzing"
xlink:href="nl.imow-mnre1034.gebiedsaanwijzing.Kustfundament"/>
<ga:GebiedsaanwijzingRef
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:ga="http://www.geostandaarden.nl/imow/gebiedsaanwijzing"
xlink:href="nl.imow-mnre1034.gebiedsaanwijzing.RGKustfundament"/>
</r:gebiedsaanwijzing>
<r:instructieregelInstrument>http://standaarden.omgevingswet.overheid.nl/instrument/id/concept/Omgevingsplan</r:instructieregelInstrument>
</r:Instructieregel>
</ow-dc:owObject>
</sl:stand>
3 <-> 1 ==================
3 <-> 2 ==================
3 <-> 2 <-> 1 ============
<sl:stand
xmlns:sl="http://www.geostandaarden.nl/bestanden-ow/standlevering-generiek">
<ow-dc:owObject
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:ow-dc="http://www.geostandaarden.nl/imow/bestanden/deelbestand">
<r:RegelVoorIedereen
xmlns:r="http://www.geostandaarden.nl/imow/regels">
<r:identificatie>nl.imow-mnre1034.juridischeregel.OR0000000027</r:identificatie>
<r:idealisatie>http://standaarden.omgevingswet.overheid.nl/idealisatie/id/concept/Exact</r:idealisatie>
<r:artikelOfLid>
<r:RegeltekstRef xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.regeltekst.OR0000000027"/>
</r:artikelOfLid>
<r:thema>http://standaarden.omgevingswet.overheid.nl/thema/id/concept/WaterEnWatersystemen</r:thema>
<r:locatieaanduiding>
<l:LocatieRef xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:l="http://www.geostandaarden.nl/imow/locatie"
xlink:href="nl.imow-mnre1034.ambtsgebied.LND6030B"/>
</r:locatieaanduiding>
</r:RegelVoorIedereen>
</ow-dc:owObject>
</sl:stand>--
Marco Duiker
LandGoed
Technisch directeur
+31617115114
MH
Martin Honnen19 Dec 2023 10:29 #
Quoted text · Marco Duiker - LandGoed · 25 lines
On 19/12/2023 09:53, Marco Duiker - LandGoed wrote: > Please help me with the following problem: > > I try to construct the current status of a series of objects along the > following simple rules: > > * the current status of on object with a certain `identificatie` > (id) is the newest version of that object > * except when the newest object has the property > `<status>beëindigen</status>` then the object stops existing. > > I use a fold-left to proces these rules with a simple function > implementing those rules. This gives me unexpected results. > > I've reduced the problem to a single stand alone query in which the > last object (`obj3`) has the property `<status>beëindigen</status>`. > > So I would expect this line: > `let $stand4 := fold-left(($obj3, $obj2, $obj1), (), function($stand, > $obj) { local:stand-totaal($stand, $obj) })` > to give me an empty result as `obj3`has the property > <status>beëindigen</status> > but I am getting `obj1` as demonstrated in the following stand alone > query. >
At least another XQuery 3.1 processor that BaseX (tried with SaxonC HE 12.4) also outputs
3 <-> 2 <-> 1 ============
<sl:stand
xmlns:sl="http://www.geostandaarden.nl/bestanden-ow/standlevering-generiek">
<ow-dc:owObject
xmlns:ow-dc="http://www.geostandaarden.nl/imow/bestanden/deelbestand"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<r:RegelVoorIedereen
xmlns:r="http://www.geostandaarden.nl/imow/regels">
<r:identificatie>nl.imow-mnre1034.juridischeregel.OR0000000027</r:identificatie>
<r:idealisatie>http://standaarden.omgevingswet.overheid.nl/idealisatie/id/concept/Exact</r:idealisatie>
<r:artikelOfLid>
<r:RegeltekstRef xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.regeltekst.OR0000000027"/>
</r:artikelOfLid>
<r:thema>http://standaarden.omgevingswet.overheid.nl/thema/id/concept/WaterEnWatersystemen</r:thema>
<r:locatieaanduiding>
<l:LocatieRef
xmlns:l="http://www.geostandaarden.nl/imow/locatie"
xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="nl.imow-mnre1034.ambtsgebied.LND6030B"/>
</r:locatieaanduiding>
</r:RegelVoorIedereen>
</ow-dc:owObject>
</sl:stand>so it looks, if that is not the result you want, as if the problem is likely in your code.
MH
Quoted text · Marco Duiker - LandGoed · 48 lines
On 19/12/2023 09:53, Marco Duiker - LandGoed wrote: > Please help me with the following problem: > > I try to construct the current status of a series of objects along the > following simple rules: > > * the current status of on object with a certain `identificatie` > (id) is the newest version of that object > * except when the newest object has the property > `<status>beëindigen</status>` then the object stops existing. > > I use a fold-left to proces these rules with a simple function > implementing those rules. This gives me unexpected results. > > I've reduced the problem to a single stand alone query in which the > last object (`obj3`) has the property `<status>beëindigen</status>`. > > So I would expect this line: > `let $stand4 := fold-left(($obj3, $obj2, $obj1), (), function($stand, > $obj) { local:stand-totaal($stand, $obj) })` > to give me an empty result as `obj3`has the property > <status>beëindigen</status> > but I am getting `obj1` as demonstrated in the following stand alone > query. > > When running the stand alone query I would *expect*: > > > declare function local:stand-totaal > (: returns an object by comparing new to old :) > (: newest should be returned, except when > <ow:status>beëindigen</ow:status> > then no object should be returned :) > ($new as item()*, > $old as item()*) as item()* { > > let $new_ids := local:id($new) > let $stand_deel1 := > for $obj_oud in $old//*:owObject > where not(local:id($obj_oud) = $new_ids) > return <sl:stand>{ $obj_oud }</sl:stand> > let $stand_deel2 := > for $obj_new in $new//*:owObject[not(.//*:status)] > return <sl:stand>{ $obj_new }</sl:stand> > > return ($stand_deel1, $stand_deel2) > }; >
From your comment and explanation I kind of would expect a check for that particular value
<ow:status>beëindigen</ow:status>but that value is not checked for or mentioned at all in the XQuery code.
HR
Hans-Juergen Rennau19 Dec 2023 11:23 #
Hi Marco,
I've also taken a look at the code and I think the observed behaviour is in accordance with the logic of the accumulator function (local:stand-totaal), while this logic is probably not really what. First - why do you get the result which you get? (1) The logic of local:stand-totaal(a) Accept the new item only if its ID is not found among the accumulated items (before filtering these for the status, see b))(b) Retain only those accumulated items which do not have a certain status
The input sequence is objects 3, 2, 1(1) Process object 3: Object accepted, as the accumulator is still empty, so the object ID is "new"; the fact that the new object has a <status> element is ignored.(2) Process object 2: The object is rejected, as its ID is found in the accumulator; the accumulator is then filtered, discarding object 3 because of its status; result: the accumulator is again empty (nothing added, and what was there has been removed)(3) Process object 1: The object is accepted, as the accumulator is again empty, so the item ID is "new" From your expectations I gather that you want to exclude later reuse of an ID possessed by an object with status "beeindigen". Therefore I suggest the following simple solution of the problem:(a) Extract all IDs of an object with that status(b) Before fold-left, filter the sequence of objects, discarding any object with such an ID(c) Process the filtered sequence, not thinking about the status any more, just checking the ID This processing is best encapsulated in a function (e.g. update-stand()). With kind regards,Hans-Jürgen
PS: Code snippet for the suggestion:
declare function local:update-stand($objects as element()*) as element()* { let $idsIGN := $objects[.//*:status = 'beëindigen']//*:identificatie => distinct-values() let $objectsF := $objects[not(.//*:identificatie = $idsIGN)] return fold-left($objectsF, (), local:stand-totaal#2) }; declare function local:stand-totaal (: returns an object by comparing new to old :) (: newest should be returned, except when <ow:status>beëindigen</ow:status> then no object should be returned :) ($new as item()*, $old as item()*) as item()* { let $new_ids := $new//*:identificatie => distinct-values() return ($new, $old[not(.//*:identificatie = $new_ids)]) };
Am Dienstag, 19. Dezember 2023 um 10:38:49 MEZ hat Martin Honnen <martin.honnen at gmx.de> Folgendes geschrieben:
Quoted text · Marco Duiker - LandGoed · 1 line
On 19/12/2023 09:53, Marco Duiker - LandGoed wrote:
Please help me with the following problem:
I try to construct the current status of a series of objects along the following simple rules:
- the current status of on object with a certain
identificatie (id) is the newest version of that object
- except when the newest object has the property <status>beëindigen</status> then the object stops existing.
I use a fold-left to proces these rules with a simple function implementing those rules. This gives me unexpected results.
I've reduced the problem to a single stand alone query in which the last object (obj3) has the property <status>beëindigen</status>.
So I would expect this line:
let $stand4 := fold-left(($obj3, $obj2, $obj1), (), function($stand, $obj) { local:stand-totaal($stand, $obj) }) to give me an empty result as obj3 has the property <status>beëindigen</status> but I am getting obj1 as demonstrated in the following stand alone query.
When running the stand alone query I would expect: declare function local:stand-totaal
(: returns an object by comparing new to old :)
(: newest should be returned, except when
<ow:status>beëindigen</ow:status>
then no object should be returned :)
($new as item()*,
$old as item()*) as item()* {
let $new_ids := local:id($new)
let $stand_deel1 :=
for $obj_oud in $old//*:owObject
where not(local:id($obj_oud) = $new_ids)
return <sl:stand>{ $obj_oud }</sl:stand>
let $stand_deel2 :=
for $obj_new in $new//*:owObject[not(.//*:status)]
return <sl:stand>{ $obj_new }</sl:stand>
return ($stand_deel1, $stand_deel2)
};From your comment and explanation I kind of would expect a check for that particular value
<ow:status>beëindigen</ow:status>but that value is not checked for or mentioned at all in the XQuery code.
ML
Marco Duiker - LandGoed19 Dec 2023 14:48 #
Hans-Jurgen,
Thank you for your detailed help. This really helped me to understand what I was doing (as opposed to what I was trying to do).
Based on your detailed comments and the following usage notes on fold-left from Priscilla Walmsley's XQuery book
"This function performs an operation (the function $f ) on two items at a time, accu‐
mulating a result as it goes. It first calls the function using $zero as the first argument
and the first item in $seq as the second argument. It then calls it a second time using
the result of the previous function call as the first argument, and the second item in
$seq as the second argument. It continues until there are no further items in $seq ."
I figured out that I reversed the two parameters in the function call, and based on that also reversed the ordering in the first argument of the fold-left. The following (note the reversal of arguments in local:stand-totaal($obj, $stand) and in the first argument of
fold-left) gives me the desired result: let $stand1 := fold-left(($obj1, $obj2) , (), function($stand, $obj)
{ local:stand-totaal($obj, $stand) })
let $stand2 := fold-left(($obj2, $obj3) , (), function($stand, $obj)
{ local:stand-totaal($obj, $stand) })
let $stand3 := fold-left(($obj1, $obj2, $obj3) , (),
function($stand, $obj) { local:stand-totaal($obj, $stand) })
return ( '1 <-> 2 ==================', $stand1,
'2 <-> 3 ==================', $stand2,
'1 <-> 2 <-> 3 ============', $stand3
)Quoted text · Hans-Juergen Rennau · 1 line
>From your expectations I gather that you want to exclude later reuse
of an ID possessed by an object with status "beeindigen". Therefore I suggest the following simple solution of the problem:
Actually, that is not the case. Later reuse must be possible.
Thank you all for the help, MArco
Quoted text · Hans-Juergen Rennau · 122 lines
On 19-12-2023 11:23, Hans-Juergen Rennau wrote: > Hi Marco, > > I've also taken a look at the code and I think the observed behaviour > is in accordance with the logic of the accumulator function > (local:stand-totaal), while this logic is probably not really what. > First - why do you get the result which you get? > > (1) The logic of local:stand-totaal > (a) Accept the new item only if its ID is not found among the > accumulated items (before filtering these for the status, see b)) > (b) Retain only those accumulated items which do not have a certain status > > > The input sequence is objects 3, 2, 1 > (1) Process object 3: Object accepted, as the accumulator is still > empty, so the object ID is "new"; the fact that the new object has a > <status> element is ignored. > (2) Process object 2: The object is rejected, as its ID is found in > the accumulator; the accumulator is then filtered, discarding object 3 > because of its status; result: the accumulator is again empty (nothing > added, and what was there has been removed) > (3) Process object 1: The object is accepted, as the accumulator is > again empty, so the item ID is "new" > > From your expectations I gather that you want to exclude later reuse > of an ID possessed by an object with status "beeindigen". Therefore I > suggest the following simple solution of the problem: > (a) Extract all IDs of an object with that status > (b) Before fold-left, filter the sequence of objects, discarding any > object with such an ID > (c) Process the filtered sequence, not thinking about the status any > more, just checking the ID > > This processing is best encapsulated in a function (e.g. update-stand()). > > With kind regards, > Hans-Jürgen > > PS: Code snippet for the suggestion: > > declare function local:update-stand($objects as element()*) > as element()* { > let $idsIGN := $objects[.//*:status = > 'beëindigen']//*:identificatie => distinct-values() > let $objectsF := $objects[not(.//*:identificatie = $idsIGN)] > return fold-left($objectsF, (), local:stand-totaal#2) > }; > declare function local:stand-totaal > (: returns an object by comparing new to old :) > (: newest should be returned, except when > <ow:status>beëindigen</ow:status> > then no object should be returned :) > ($new as item()*, > $old as item()*) as item()* { > let $new_ids := $new//*:identificatie => distinct-values() > return ($new, $old[not(.//*:identificatie = $new_ids)]) > }; > > > Am Dienstag, 19. Dezember 2023 um 10:38:49 MEZ hat Martin Honnen > <martin.honnen at gmx.de> Folgendes geschrieben: > > > > On 19/12/2023 09:53, Marco Duiker - LandGoed wrote: >> Please help me with the following problem: >> >> I try to construct the current status of a series of objects along >> the following simple rules: >> >> * the current status of on object with a certain `identificatie` >> (id) is the newest version of that object >> * except when the newest object has the property >> `<status>beëindigen</status>` then the object stops existing. >> >> I use a fold-left to proces these rules with a simple function >> implementing those rules. This gives me unexpected results. >> >> I've reduced the problem to a single stand alone query in which the >> last object (`obj3`) has the property `<status>beëindigen</status>`. >> >> So I would expect this line: >> `let $stand4 := fold-left(($obj3, $obj2, $obj1), (), function($stand, >> $obj) { local:stand-totaal($stand, $obj) })` >> to give me an empty result as `obj3`has the property >> <status>beëindigen</status> >> but I am getting `obj1` as demonstrated in the following stand alone >> query. >> >> When running the stand alone query I would *expect*: >> >> >> declare function local:stand-totaal >> (: returns an object by comparing new to old :) >> (: newest should be returned, except when >> <ow:status>beëindigen</ow:status> >> then no object should be returned :) >> ($new as item()*, >> $old as item()*) as item()* { >> >> let $new_ids := local:id($new) >> let $stand_deel1 := >> for $obj_oud in $old//*:owObject >> where not(local:id($obj_oud) = $new_ids) >> return <sl:stand>{ $obj_oud }</sl:stand> >> let $stand_deel2 := >> for $obj_new in $new//*:owObject[not(.//*:status)] >> return <sl:stand>{ $obj_new }</sl:stand> >> >> return ($stand_deel1, $stand_deel2) >> }; >> > From your comment and explanation I kind of would expect a check for > that particular value > > <ow:status>beëindigen</ow:status> > > but that value is not checked for or mentioned at all in the XQuery code. > > >
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Marco Duiker
LandGoed
Technisch directeur
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