How to return all elements in an element range index in Marklogic

I have the following element in my XML:

<series id="iot" type="main">Institute of Theology</series>


What I am trying to do is to get all series values in the database along with the matching @id value in the most performance conscious way possible. I have set up an element range index on <series/> and also an attribute range index on @id. I've tried using cts:element-values() which works great to get the series element values, but I can't figure out how to return both the element and matching id values.

@id

<series/>

@id

cts:element-values()

The end result I'm looking for should be like this:

iot Institute of Theology


2 Answers
2

You can get tuples of index values using cts:value-tuples.

cts:value-tuples

For example, this will return pairs of series/@id and series:

series/@id

series

cts:value-tuples((
cts:element-attribute-reference(xs:QName('series'), xs:QName('id')),
cts:element-reference(xs:QName('series'))
))


However, the pairs will only be accurate within <series> if there is only one <series> per document. Otherwise you will get all of the combinations of series/@id and series per document, regardless of whether they are from the same element.

<series>

<series>

series/@id

series

If that is the case, then your options are to either change your documents (or use fragment roots, which is probably not a good idea), or use another method like Template Driven Extraction, where the pairs could be projected into a "stand-off" index, like rows, and then queried separate from the document context.

With a few small changes to wst's answer I was able to solve this. The XML I'm working with does indeed have more than one <series> element per document, but I found a workaround by using the "proximity=N" option in cts:value-tuples(). Setting proximity to 0 returned the @id and the closest series title.

<series>

cts:value-tuples()

@id

Here's the code:

for $tuple in
cts:value-tuples((
cts:element-attribute-reference(xs:QName("ia:series"), xs:QName('id')),
cts:element-reference(xs:QName("ia:series"))
), "proximity=0")
let $values := json:transform-from-json($tuple)
return
for $value in $values
let $id := $value/jsonNS:item[1]
let $title := $value/jsonNS:item[2]
return fn:concat($id, " | ", $title)


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