Jakob, I want to highlight that Charles' code uses range index values on both "sides" of the join. He pulls values using element-values(), so that comes from a range index. Then he uses element-range-query() to do the shotgun OR. This is important because the values will line up properly (particularly if they use the default collation or if you have a non-default collation set both indexes use the same one).
Word queries apply stemming and ignore punctuation. Value queries can even be a little different from the values in the range indexes, so use range indexes on both sides of the join. Yours, Damon From: [email protected] [mailto:[email protected]] On Behalf Of Charles Greer Sent: Tuesday, January 08, 2013 10:56 AM To: MarkLogic Developer Discussion Subject: Re: [MarkLogic Dev General] "left join" using search:search or cts:search? Hi Jakob, The way to accomplish this kind of thing using cts:search is pretty well understood right now. Use a "scatter query" or "shotgun OR" technique -- use cts:values to fetch the identifiers from chapter documents that interest you (with a subquery as needed) Then use the output of that that call as input to a cts:search on book documents. let $vals := cts:values($index-reference-with-book-identifiers, 0, (), cts:query("for chapters")) return cts:search(/, cts:element-range-query(xs:QName("bookid"), "=", $vals) This runs quickly because it's all XQuery on the server. There's no corresponding technique in search API at this time, although with a custom constraint one could accomplish it. It's on my todo list to provide examples of this kind of custom code... The technique would be to make an XQuery module with this kind of code in it, and then define a custom constraint that would invoke it, so book:term-in-chapter would put "term-in-chapter" into the first clause above, and then the extension would return results from the cts:search. Hope that helps a little. There's good discussion of this technique in the "Inside MarkLogic" paper by Jason Hunter. Charles On 01/08/2013 07:29 AM, Jakob Fix wrote: Hi, Is it possible to find documents based on a criteria match on a related document with the search:search (or cts:search) api ? To explain: I have separate documents for books and chapters, where each chapter has a reference to their parent book via an identifier, and I would like to find books which contain either a specific term themselves or in one of their chapters. I can't seem to find a way with the cts:query to make something like a left join in SQL. thanks, Jakob. _______________________________________________ General mailing list [email protected]<mailto:[email protected]> http://developer.marklogic.com/mailman/listinfo/general -- Charles Greer Senior Engineer MarkLogic Corporation [email protected]<mailto:[email protected]> Phone: +1 707 408 3277 www.marklogic.com<http://www.marklogic.com>
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