Mongo用户定义的函数和Map Reduce [英] Mongo User Defined Functions and Map Reduce

问题描述

mongo中是否有一种创建用户定义的Javascript函数的方法.我想在其他MR函数中使用一些客户端的Map/Reduce函数.

Is there a way in mongo to create user-defined Javascript functions. I have several Map/Reduce functions on the client side that i would like to use within other MR functions.

例如，几个MR函数计算各种平均值.我希望能够像这样使用它们:

For example, several MR functions calculate all sorts of averages. I want to be able to use them like so :

function reduce(k,v)
{
    if (val > myDatabaseAverage())
    // ..do something
}

推荐答案

使用db.system.js.save({_id:"myDatabaseAverage"，value:function(){//..do something}}));

Use db.system.js.save( { _id : "myDatabaseAverage" , value : function(){ // ..do something } } );

这会将JS函数存储在服务器上，并且从那以后m/r可以对其进行访问.

That will store the JS function on the server and can be accessed by m/r from that point on.

有关更多示例，请参见: https://github.com/mongodb/mongo/blob/master/jstests/storefunc.js

For further examples see : https://github.com/mongodb/mongo/blob/master/jstests/storefunc.js

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