使用 MongoDB $pull 删除数组中的文档
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Using MongoDB $pull to delete documents within an Array
提问by VaidAbhishek
I have a collection in MongoDB, which is like following:
我在 MongoDB 中有一个集合，如下所示：
{
"_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"
}
]
}
Basically, collection have clusters, where a cluster has an _idfield and a membersfield. Members field is an array of documents, having following format.
基本上，集合有集群，其中集群有一个_id字段和一个members字段。成员字段是一个文档数组，具有以下格式。
{
"participationCoeff" : 1,
"tweetID" : "5327010328645530500"
}
Now, from time to time, I have to delete these sub-documents in members attribute of cluster document, by matching tweetID.
现在，我有时必须通过匹配 tweetID 来删除集群文档的 members 属性中的这些子文档。
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.
但是，我无法找到实现此效果的查询。基本上，一个tweetID会参与很多集群，因此会出现在各个集群的'members'属性的多个子文档中。我想提供一个批量 $pull 操作，在那里我可以删除所有集群中的所有子文档（即它们的成员属性），这些子文档与特定的 tweetID 匹配。
Some help and intuition will be really helpful.
一些帮助和直觉将非常有帮助。
回答by JohnnyHK
That's exactly what the $pulloperator does, so in the shell you could use an updatelike:
这正是$pull操作符所做的，所以在 shell 中你可以使用update类似的：
db.clusters.update({},
{$pull: {members: {tweetID: '5327010328645530500'}}},
{multi: true})
Set the multioption so that every document is updated, not just the first one.
设置multi选项以便更新每个文档，而不仅仅是第一个。
回答by Amit Kumar
This will delete multiple tweetsin a single query just pass an array to $in:-
这将multiple tweets在单个查询中删除，只需将数组传递给$in：-
db.clusters.update({},
{$pull: {members: {$in: [ {tweetID: '5327010328645530500'},{"tweetID" : "2820402625046999289"} ] } } },
{multi: true});
The above method doesnt work in mongoose so for mongoose do:-
上述方法在猫鼬中不起作用，因此对于猫鼬来说：-
db.clusters.update({},
{$pull: {members:[ {tweetID: '5327010328645530500'},{"tweetID" : "2820402625046999289"} ] } });
