MarkLogic-XQuery-使用可变长度序列或映射的cts：element-range-query

Question

I have a collection of 100,000 records structured like this:

<record>
    <pk>1</pk>
    <id>1234</id>
</record>
<record>
    <pk>2</pk>
    <id>1234</id>
</record>
<record>
    <pk>3</pk>
    <id>5678</id>
</record>
<record>
    <pk>4</pk>
    <id>5678</id>
</record>

I have setup a range index on id.

I want to write a query in XQuery that will allow me to pass in a variable length sequence or map of id's and get back out all the records with those id's.

It needs to be such that I can pass in any number of id's. Also, it needs to take advantage of the range index (as in fast).

Answer 1

CTS searches are your friend. They will use your indexes.
You have a few different options with your CTS search. My first thought is to try something like this:

let $ids as xs:string* := (1, 2, 4, 5, 6, 33, 35.....89)
let $results as element(record)* := cts:search(/record,
    cts:element-value-query(xs:QName("id"), $ids, ("exact"))
    )
return $results
(: This will return all the record elements with their children :)

The documentation shows that you can specify a sequence as the second parameter in your cts:element-value-query , and your sequence by very nature is variable length. When your sequence is passed into that cts:element-value-query , it is as if to say "ID==3 OR ID==9 OR ID==13", etc.

http://docs.marklogic.com/7.0/cts:element-value-query

You can also use an element range query: http://docs.marklogic.com/7.0/cts:element-range-query , though I'm not as good with those so I can't give you very much help on that.

Note that in my code above, I have put the ids as xs:string s. You can of course have them as xs:integer s, and but either way they will be parsed as strings when passed in the parameter.