mongodb - Need a map reduce function in mongo using php -

-

need map reduce function mongo in php

this mongo structure

[_id] => mongoid object (     [$id] => 4fcf2f2313cfcd2454500000d ) [id] => 454 [table] => people [news] => array (     [03-06-2012] => 2     [04-06-2012] => 3     [05-06-2012] => 5     [06-06-2012] => 4 )

here try sum array news below code, 

    $map = new mongocode('function() { emit(this.news, 1); }');     $reduce = new mongocode('function(previous, current) {                     var count = 0;                     (index in current) {                         count = count + current[index];                     }                     return count;                 }');      $sales = $db->command(array(         'mapreduce' => 'mycollection',         'map' => $map,         'reduce' => $reduce,         'query' => array('table' => 'people'),         'out'  => 'news'     ));      //pr($sales);exit;      $users = $db->selectcollection($sales['result'])->find();      foreach ($users $user) {         //echo "{$user['_id']} had {$user['value']} sale(s).\n";         pr($user);     }

when pr($user) 

array (     [_id] => array     (         [04-06-2012] => 0         [08-06-2012] => 2         [11-06-2012] => 6     )      [value] => 39540 )

where expected value 8 instead of 39540.

how can correct function , how add field sum array sum of 'news' original collection(mycollection) ?

i not familar map reduce functions in mongo.

when calling emit(), first parameter key you'll reducing on (or grouping, example). second parameter value being emitted key, can anything. example, mean emit sum of values in news field, using document's id key:

var map = function() {     var total = 0;     (count in this.news) {         total += count;     }     emit(this._id, total); }

in case, placeholder reduce function can used (since each emitted key unique, there's little reduction done):

var reduce = function(key, values) {     var total = 0;     values.foreach(function(v) { total += v; });     return total; }

however, mentioned in google group post, may better off doing pure php:

$cursor = $collection->find(array(), array('news' => 1)); $cursor->snapshot();  foreach ($cursor $document) {     $collection->update(         array('_id' => $document['_id']),         array('$set' => array('sum' => array_sum($document['news']))),         array('multiple' => false)     ); }

with map/reduce, you'd still have examine results , update records. avoid need execute javascript through mongo, , should more performant. , if can utilize $inc update sums news field modified on per-document basis, better. above snippet still useful initializing sum fields across collection, or correcting drift if things out of sync per-document increments.

note: see snapshot() in documentation reasoning behind method call in example above.


Comments

Post a Comment

Popular posts from this blog

django - How can I change user group without delete record -

-
on website user have 1 group. , user can change group. it's made user.groups.clear() and user.groups.add(new_group) but it's not efficient, because there 2 sql query: delete, insert. how can change group update query? user , group related each other using manytomanyfield . means intersection table exists relating both entities, , if don't specify model map (using through attribute) django creates 1 you. looking @ sources django.contrib.auth.models see that's case. fortunatly, can access intermediary model using through attribute of manager (in case, user.groups.through ). can use regular model. example: >>> alice = user.objects.create_user('alice', 'alice@example.com', 'alicepw') >>> employee = group.objects.create(name='employee') >>> manager = group.objects.create(name='manager') >>> alice.groups.add(employee) >>> alice.groups.all() [<group: employee...
Read more

java - Need to add SOAP security token -

-
i need set custom soap header attribute on jax-ws generated webservice client. case webservice calls must go through proxy server requiring specific token (recieved web request header) present in soap request header. e.g.: 1 carserviceservice service = null; 2 service = new carserviceservice(new url(url), new qname(qname); 3 carserviceendpoint port = service.getcarserviceport(); it seems in line 3 wsdl retrieved , call fails due missing security token. 1 point direction on how done? a detailed example has been mentioned here: creating , deploying jax-ws web service on tomcat 6 this article shows how create , use security token .
Read more

java - EclipseLink JPA Object is not a known entity type -

-
i have strange problem eclipselink , object want persist. have 1 object (keypointlistimpl) stores object keypointimpl in list. persisting keypointimpl objects works great if try persist keypointlistimpl object java.lang.illegalargumentexception says object keypointimpl isn't known entity type. here keypointimpl code: @entity @table(name="keypoints") public class keypointimpl implements keypoint { @id @generatedvalue(strategy = generationtype.identity) private int id; @enumerated(enumtype.string) private detectortype keypointtype; private float x; private float y; private float size; private float angle; private float response; private int octave; private int classid; ... } here keypointlistimpl code: @entity @table(name="keypointlists") public class keypointlistimpl implements keypointlist { @id @generatedvalue(strategy = generationtype.identity) private int id; @onetoone(cascade={ca...
Read more