On Fri, Jan 8, 2010 at 6:10 AM, Borja Martín <[email protected]> wrote: > Hi, > suppose I have the typical view used to index the tags of a document: > > // map > function(doc) { > for (var idx in doc.tags) { > emit(doc.tags[idx], 1); > } > } > > // and then I have this reduce function to count how many documents I have > for each given tag: > function(key,values) { > return sum(values); > } > > and with the following sample documents: > { "tags" : ["foo", "foo bar"] }, > { "tags" : ["foo", "bar", "foo bar"]} > > I get these results: > {"rows":[ > {"key":"bar","value":1}, > {"key":"foo","value":3}, > {"key":"foo bar","value":2} > ]} > > What I want to do is to get the results ordered by its value so I can know > which are the most used tags for example. I know that the results are > ordered by the key so I guess this could be done if I could use the value > returned by the reduce on it while calling the emit function with something > like emit([reduce_value, tag], null); Is there any way to accomplish that? >
This is a common request, but not supported directly by CouchDB's views -- to do this you'll need to copy the group-reduce query to another database, and build a view to sort by value. This is a tradeoff we make in favor of dynamic range queries and incremental indexes. Chris > Has it sense or am I misunderstanding something? > > Thanks in advance > > Regards > > -- > def dagi3d(me) > case me > when :web then "http://dagi3d.net"; > when :twitter then "http://twitter.com/dagi3d"; > end > end > -- Chris Anderson http://jchrisa.net http://couch.io
