I was thinking about something like this (correct me if this is a
stupid way of doing it):
For the map function of the view I have:
function(doc) {
for(var i = 3, i <= doc.name.length; i++){
emit(doc.name.substring(0, i), doc);
}
}
This will create several keys for each doc. For the city "new york" it
would create the following keys:
"new", "new ", "new y", "new yo", "new yor", "new york".
This way I can search for all cities starting with the name "new" like
this: "?key=new" and this will return all cities with the "new" key
right?
To limit the result I create a reduce function like this:
function(keys, values, rereduce) {
var vals = [];
var resultLength = 20;
for(var i = 0; i <= values.length;i++){
if(vals.length <= resultLength){
vals.push(values[i]);
}
else{
vals.sort(function(a,b){
return b.population - a.population;
});
if(vals[resultLength - 1].population <
values[i].population){
vals.pop();
vals.push(values[i]);
}
}
}
}
What this function does is that it creates an array of the x (defined
in the reduce function) largest cities and return them.
The downside of this is that the number of return cities is defined in
the result function but I can live with that.
Will this work as I expect? Will this have a large impact on the size
of the database? Does all keys point at the same document? Or is all
the documents store once for each key? Have I understand how the
reduce function works correctly?
Magnus
On Mon, Apr 12, 2010 at 11:34 AM, Nils Breunese <[email protected]> wrote:
> I'm sorry, I totally misread your use case. Yes, you are correct. Forget what
> I said. :o)
>
> I found couchdb-footrest a while ago, which apparently features 'Order Docs
> By Value Fields': http://github.com/assembly/couchdb-footrest Sadly, I never
> got couchdb-footrest to work.
>
> Like others have suggested: I think you'll want to go and look into
> couchdb-lucene, which will certainly do what you're looking for:
> http://github.com/rnewson/couchdb-lucene
>
> Nils Breunese.
> ________________________________________
> Van: Magnus Ottosson [[email protected]]
> Verzonden: maandag 12 april 2010 11:19
> Aan: [email protected]
> Onderwerp: Re: Search for city by name, order by population
>
> Are you sure about that?
>
> Wouldn't [name, population] first order the cities by name and if
> there are more than one city with the same name they would be order by
> population?
>
> Magnus
>
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