Mailing-List: contact user-help@couchdb.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@couchdb.apache.org
Received-SPF: pass (nike.apache.org: domain of zachary.zolton@gmail.com
 designates 209.85.160.52 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <37E896DC-095B-4AAA-AA5C-67AAE7C3B46D@p3k.org>
References: <37E896DC-095B-4AAA-AA5C-67AAE7C3B46D@p3k.org>
From: Zachary Zolton <zachary.zolton@gmail.com>
Date: Fri, 6 Jan 2012 11:57:59 -0600
Message-ID: 
 <CAGnHtbKVHLc_Mbi4rDDwdpxhzcrj2-oA94Uw-1MH8UmcZF1gPg@mail.gmail.com>
Subject: Re: Newbie question: How to collate sum() with other properties
To: user@couchdb.apache.org
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: quoted-printable

Tobi,

You probably can somehow cram all that stuff together via the reduce
function, but you miss out on being able to use the built in _count
reduction and it'll take a mess of code.

I think you're better off trying to retrieve this information in two
queries: first query for the names and IDs of the polls and then do a
second query for the count of choices of those poll IDs.


Cheers,

Zach


2012/1/6 Tobi Sch=E4fer <interface@p3k.org>:
> Hello
>
> I am developing a little survey / poll tool as a first step in practicing=
 CouchDB.
>
> There are poll and vote documents stored in the database:
>
> poll =3D {
> =A0 _id: 'd193f1137ddb65aa14100a51dc61b17e',
> =A0 type: 'poll',
> =A0 title: 'What is the question?',
> =A0 choices: ['Choice 1', 'Choice 2, 'Choice 3'],
> =A0 date: new Date
> }
>
> vote =3D {
> =A0 poll_id: 'd193f1137ddb65aa14100a51dc61b17e',
> =A0 type: 'vote',
> =A0 choice: 'Choice 1',
> =A0 date: new Date
> }
>
> Now I am trying to create a view of all polls together with their aggrega=
ted votes for each choice as well as the total votes:
>
> map: function(doc) {
> =A0 if (doc.type =3D=3D=3D 'poll') {
> =A0 =A0 =A0emit([doc._id, doc.date], {title: doc.title});
> =A0 } else if (doc.type =3D=3D=3D 'vote' && doc.choice) {
> =A0 =A0 =A0emit([doc.poll_id, doc.choice], {count: 1, title: doc.choice})=
;
> =A0 =A0 =A0emit([doc.poll_id, '_total'], {count: 1, title: doc.choice});
> =A0 }
> },
>
> reduce: function(key, values) {
> =A0 var i, value, result =3D {count: 0};
> =A0 for (i in values) {
> =A0 =A0 =A0value =3D values[i];
> =A0 =A0 =A0result.title =3D value.title;
> =A0 =A0 =A0if (value.count) {
> =A0 =A0 =A0 =A0 result.count +=3D 1;
> =A0 =A0 =A0} else {
> =A0 =A0 =A0 =A0 delete result.count;
> =A0 =A0 =A0}
> =A0 }
> =A0 return result;
> }
>
> This seems to work but I am not sure if I will run into =93rereduce troub=
le=94:
>
> ["d193f1137ddb65aa14100a51dc235509", "2012-01-05T15:36:40.632Z"]
> {title: "What is the amazingly accurate answer to the ultimate question o=
f life, the universe and everything?"}
> ["d193f1137ddb65aa14100a51dc235509", "_total"] =A0 =A0 =A0 =A0 =A0{count:=
 7, title: "6 =B7 9"}
> ["d193f1137ddb65aa14100a51dc235509", "101010"] =A0{count: 2, title: "1010=
10"}
> ["d193f1137ddb65aa14100a51dc235509", "42"] =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0{count: 3, title: "42"}
> ["d193f1137ddb65aa14100a51dc235509", "6 =B7 9"] =A0 =A0 =A0 =A0 =A0 {coun=
t: 1, title: "6 =B7 9"}
> ["d193f1137ddb65aa14100a51dc235509", "XLII"] =A0 =A0 =A0 =A0 =A0 =A0{coun=
t: 1, title: "XLII"}
>
> What do you think? Is there an easier or more convenient way to create su=
ch a view?
>
> Best regards,
> Tobi Sch=E4fer
>