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Date: Mon, 27 Apr 2009 22:42:41 -0700
From: Paul Davis <paul.joseph.davis@gmail.com>
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To: user@couchdb.apache.org
Subject: Re: map/reduce function question
References: <dbabc8c20904271932tf08f226nc31b0d82327d1784@mail.gmail.com>
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Kevin,

You'll want to do something like this:

{
    "_id": "_design/foo",
    "views": {
        "unique_names": {
            "map": "function(doc) {emit(doc.name, 1);}",
            "reduce": function(keys, values, rereduce) {return 
sum(values);}"
       }
    }
}

And then you can call this like:

    http://127.0.0.1:5984/db_name/_design/foo/_view/unique_names

to get ouput like

{"rows": [
    {"key": null, "value": 3}
}

HTH,
Paul Davis

Kevin Wang wrote:
> Hi All,
>
> While I am trying to switch my mind to map/reduce model while accessing
> couchdb data, I found myself struggling.  Here is a simple question that you
> guys might be able to answer:
>
> If I have the following set of data in a doc:
>
> {"name": "foo", "prop": "value1"}
> {"name": "bar", "prop": "value2"}
> {"name": "foo", "prop": "value3"}
> {"name": "bob", "prop": "value4"}
>
> How to write the map/reduce functions so that I can get a view which returns
> the total number of unique name's?  In this case, the result should be 3.
>
> Thanks!
>
> -- Kevin
>
>