That's perfect, thanks Robert. Funny how something so simple can be so
confusing if the concept is new to you.......
For anyone who searches for how to do a reduce over an array in the future,
here's the code:
function(keys, values, rereduce){
var total = [0,0];
values.forEach(function(value){
total[0] += value[0];
total[1] += value[1];
}
)
return total;
}
Looks like I might get to add reporting to my successful use cases for Couchdb!
John
On 31 Jan 2011, at 09:01, Robert Newson wrote:
> in 1.1, _sum will work for arrays of numbers too (rather than
> concatenating them as above). for now, just loop over the array of
> arrays and do the sum yourself.
>
> On Mon, Jan 31, 2011 at 1:02 AM, Keith Gable <[email protected]>
> wrote:
>> It sounds like you need a new view for each piece of data.
>>
>> by_answered, by_busy, by_time_to_answer, etc.
>>
>> Then you'd query each view to get the reduction, and the reduce would be as
>> simple as _sum.
>>
>>
>>
>> On Jan 30, 2011, at 5:55 PM, John <[email protected]> wrote:
>>
>>> Hi
>>>
>>> I'm looking to extend our usage of couchdb by replacing our mysql
>>> reporting db.
>>> Whilst using couchdb successfully for a number of varied use cases I've
>>> never had to do much with reduce so I'm unsure on how to use it to reduce an
>>> array of values.
>>>
>>> Basically I want to be able to search a database using a composite key and
>>> retrieving some aggregated information about number of calls, call status,
>>> avg time to answer and avg duration
>>>
>>>
>>> The following view shows how I'd like it to work:
>>>
>>> Key = <Application, Account, Subscription>
>>> Value = <1, answered, busy, noreply, time to answer, duration>
>>>
>>> e.g.
>>>
>>> ["NTS", "NetDev", "MySub1"], [1,1,0,0,100,200]
>>> ["NTS", "NetDev", "MySub1"], [1,1,0,0,150,400]
>>> ["NTS", "NetDev", "MySub1"], [1,1,0,0,170,500]
>>> ["NTS", "NetDev", "MySub1"], [1,0,1,0,0,0]
>>> ["NTS", "NetDev", "MySub1"], [1,0,1,0,0,0]
>>> ["NTS", "NetDev", "MySub1"], [1,0,0,2,0,0]
>>> ["NTS", "NetDev", "MySub1"], [1,0,0,2,0,0]
>>>
>>> My Reduced output should look like this:
>>>
>>> [7,3,2,2,420,1100]
>>> i.e. 7 calls in total, 3 answered, 2 busy, 2 no reply, the total time for
>>> time to answer is 420 and the total time for call duration is 1100.
>>>
>>> I can then compute the two averages after getting the data back from couch
>>> i.e. 420/no. of answered calls(3) and 1100/no. of answered calls(3)
>>>
>>> I thought that sum(values) would do this for me but it just upsets couch:
>>>
>>> Reduce output must shrink more rapidly: Current output:
>>> '["001,11,11,11,11,11,11,11,11,11,11,101,11,11,11,11,11,11,11,11,11,11,11,101,11,11,11,11,11,11,11,11'...
>>> (first 100 of 277 bytes)
>>>
>>> What should my reduce function look like?
>>>
>>> Thanks
>>>
>>> John
>>
