I could need some advice on how to handle a particular cross language search with Solr. I posted it on Stackoverflow 2 months ago, but could not find a solution. I have documents in 3 languages (English, German, French). For simplicity let's assume it's just two languages (English and German). The documents are standardised in the sense that they contain the same parts (text_part1 and text_part2), just the language they are written in is different. The language of the documents is known. In my index schema I use one core with different fields for each language.
For a German document the index will look something like this: * text_part1_en: empty * text_part2_en: empty * text_part1_de: German text * text_part2_de: Another German text For an English document it will be the other way around. What I want to achieve: A user entering a query in English should receive both, English and German documents that are relevant to his search. Further conditions are: * I want results with hits in text_part1 and text_part2 to be higher ranked than results with hits only in one field (tie value > 0). * The queries will not be single words, but full sentences (stop word removal needed and partial hits [only a few words out of the sentences] must be valid). * English and German documents must output into one ranking. I need to be able to compare the relevance of an English document to the relevance of a German document. * the text parts need to stay separate, I want to boost the importance of (let's say part1) over the other. My general approach so far has been to get a German translation of the user's query by sending it to a translation API. Then I want use an edismax query, since it seems to fulfill all of my requirements. The problem is that I cannot manage to search for the German query in the German fields and the English query in the English fields only. The Solr edismax documentation<https://lucene.apache.org/solr/guide/6_6/the-extended-dismax-query-parser.html> states that it supports the full Lucene query parser syntax, but I can't find a way to address different fields with different inputs. I tried: q=text_part1_en: (A sentence in English) text_part1_de: (Ein Satz auf Deutsch) text_part2_en: (A sentence in English) text_part2_de: (Ein Satz auf Deutsch) qf=text_part1_en text_part2_en text_part1_de text_part2_de This syntax should be in line with what MatsLindh wrote in this thread<https://stackoverflow.com/questions/53371028/different-search-term-on-different-fields-using-edismax-query-parser-in-solr>. I tried different versions of writing this q, but whatever I do Solr always search for the full q string in all four fields given by qf, which totally messes up the result. Am I just making mistakes in the query syntax or is it even possible to do what I'm trying to do using edismax? Any help would be highly appreciated.
