On Mon, Mar 16, 2009 at 12:11 PM, karthik c <karthik...@gmail.com> wrote:
> Hi, > > We have a requirement to fetch a set of distinct values of a given field > that match the given query. We also need to fetch the number of items > associated with each field value. I figured out a way to do this for > single-valued fields but am not able to get it to work for multi-valued > fields. > > Long Story: > Say you have an index of movies, I would like to get a unique set of > directors matching a query (say "john") and also the number of movies > directed by each of them. For this example lets assume that "director" is a > single valued field. > > I came up with one approach to implement this: Search for the query string > in the director field and then apply faceting on the same field (director). > The search will limit the movie results to the ones directed by directors > matching the query. Further, the faceting will provide a unique set of > directors and also the count of movies associated with them. The query will > look something like this: > > solr/Movie/select/?q=director:(john)&start=0&rows=0&facet=true&facet.field=raw_director > > This query works fine for single-valued fields. However it does not work in > the case of multi-valued fields, say we perform a similar search on the > "actors" (mutli-valued) field, the query will look like: > > solr/Movie/select/?q=actors:(john)&start=0&rows=0&facet=true&facet.field=raw_actors > In this case, the search will again limit the movie results to the ones in > which actors matching the query have acted in. However while faceting the > results on "actors", the facet results will also contain other actors that > have acted in the resulting movies. For eg: say we are searching for > actors:malkovich, this will return all movies in which John Malkovich has > acted in. When the faceting is applied on these results, the facet results > contain John Malkovich with the correct number of movies. But, the facet > results also contain other actors who have acted with John Malkovich. The > facet results for the above query look something like this: > <lst name="facet_fields"> > <lst name="raw_actors"> > <int name="John Malkovich">49</int> > <int name="Catherine Deneuve">4</int> > <int name="John Cusack">3</int> > <int name="Angelina Jolie">2</int> > <int name="Evangeline Lilly">2</int> > <int name="Glenne Headly">2</int> > <int name="Jeremy Irons">2</int> > <int name="Ray Winstone">2</int> > </lst> > </lst> > The other actors in the above results is obviously not what we expect to > see, since they do match the original query (i.e. malkovich). > Note that a document in your index represents a movie. You are actually searching for movies and not actors. Looking from that perspective, the results are correct. You may need to re-think your schema. Make a document represent what you want to search. Perhaps have different types of documents for 'actors', 'movies' etc. -- Regards, Shalin Shekhar Mangar.
