使用MongoDB $ pull删除数组中的文档 [英] Using MongoDB $pull to delete documents within an Array

问题描述

我在MongoDB中有一个集合，如下所示:

I have a collection in MongoDB, which is like following:

{
    "_id" : "5327010328645530500",
    "members" : [
        {
            "participationCoeff" : 1,
            "tweetID" : "5327010328645530500"
        },
        {
            "participationCoeff" : 1,
            "tweetID" : "2820402625046999289"
        },
        {
            "participationCoeff" : 0.6666666666666666,
            "tweetID" : "6122060484520699114"
        },
        {
            "participationCoeff" : 1,
            "tweetID" : "4656669980325872747"
        }
    ]
}
{
    "_id" : "2646953848367646922",
    "members" : [
        {
            "participationCoeff" : 1,
            "tweetID" : "2646953848367646922"
        },
        {
            "participationCoeff" : 0.75,
            "tweetID" : "7750833069621794130"
        },
        {
            "participationCoeff" : 0.5,
            "tweetID" : "6271782334664128453"
        }
    ]
}

基本上，集合具有群集，其中群集具有_id字段和members字段.成员字段是一系列文档，格式如下.

Basically, collection have clusters, where a cluster has an _id field and a members field. Members field is an array of documents, having following format.

{
            "participationCoeff" : 1,
            "tweetID" : "5327010328645530500"
        }

现在，我不得不不时地通过匹配tweetID删除群集文档的member属性中的这些子文档.

Now, from time to time, I have to delete these sub-documents in members attribute of cluster document, by matching tweetID.

但是，我无法找到查询来实现此效果.基本上，tweetID将参与许多群集，因此将出现在各个群集的成员"属性的多个子文档中.我想提供一个批量$ pull操作，在这里我可以删除所有集群中所有与特定tweetID相匹配的子文档(即它们的member属性).

However, I'm not able to find a query to achieve this effect. Basically, a tweetID will participate in many clusters, and hence will appear in multiple sub-documents of 'members' attribute of various clusters. I want to supply a bulk $pull operation, where I can remove all the sub-documents in all the clusters (i.e. their members attribute) which match on a particular tweetID.

一些帮助和直觉将非常有帮助.

Some help and intuition will be really helpful.

推荐答案

这正是$pull运算符的作用，因此在shell中可以使用update，如:

That's exactly what the $pull operator does, so in the shell you could use an update like:

db.clusters.update({}, 
    {$pull: {members: {tweetID: '5327010328645530500'}}}, 
    {multi: true})

设置multi选项，以便更新每个文档，而不仅仅是第一个.

Set the multi option so that every document is updated, not just the first one.

这篇关于使用MongoDB $ pull删除数组中的文档的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！