[英]MongoDB Find All Matching array, return all not just unique
I have a user collection. 我有一个用户集合。 In that collection each user when they enter a prize will have the prize id stored on their profile.
在该集合中,每个用户输入奖品时,奖品ID将存储在其个人资料中。 Export of a typical user document below
在下面导出典型的用户文档
{
"_id" : ObjectId("5aacff47c67f99103bcbf693"),
"firstName" : "Test",
"lastName" : "Test",
"password" : "$2a$10$mJjzPFWuYPmK8A07nc284O8g9SStFpuaVzfyWOZgaCmVaomIxk5qO",
"email" : "test1@test.com",
"points" : NumberInt(6),
"prizes" : [
ObjectId("5aafd1673a5b2cb294b69620"),
ObjectId("5aafd1673a5b2cb294b69620"),
ObjectId("5aafd1673a5b2cb294b69620"),
ObjectId("5aafd1673a5b2cb294b69620"),
ObjectId("5aafd1673a5b2cb294b69620"),
ObjectId("5ab28ca784aa6390aa5a1dba")
],
"messages" : [
],
"__v" : NumberInt(26)
}
I wrote a api call that when a user lands on their account page, it finds the user and returns their prize entires (array of prizes). 我写了一个api调用,当用户登陆其帐户页面时,它将找到该用户并返回其全部奖励(奖励阵列)。 I then want to use these to query the DB to find the title/content of each entry so it can be displayed on the front end.
然后,我想使用这些查询数据库来查找每个条目的标题/内容,以便可以将其显示在前端。
I've done this two ways 我已经做到了两种方式
var prizes = user.prizes
//mongo
ids = prizes.map(function(el) { return mongoose.Types.ObjectId(el) })
Prize.aggregate([
{ $match: { "_id": { "$in": ids } } }
], function(err, ret){
if (err) {
return res.status(500).json({
title: 'An error occurred',
error: err
});
}
console.log(ret)
}
)
or 要么
Prize.find( { _id: prizes }, { title: 1, content: 1 }, function(err, ret){
if (err) {
return res.status(500).json({
title: 'An error occurred',
error: err
});
}
console.log(ret)
})
Now the difficult part, both of these operations only return unique documents, (2) and not the 6 I wanted. 现在最困难的部分是,这两个操作仅返回唯一的文档(2),而不返回我想要的6个文档。
I wanted to find for every entry id then return that prize id's title and content , without caring if unique or not or have a count in response, so giving my user above it would return 我想查找每个条目ID,然后返回该奖项ID的标题和内容,而不关心是否唯一或是否有响应,因此给我高于它的用户将返回
{1x unique doc count 4} {1x unique doc, count 1} {1x唯一文档数4} {1x唯一文档数1}
or return 6 responses. 或返回6个响应。
Even when I used the .count(), it only counted 2. I know I must be going about this the wrong way, as mongo is correct in that i'm asking it to find the documents matching the id's I pass it and it finds the 2 matching id's and serves them up. 即使当我使用.count()时,它也只计为2。我知道我一定会以错误的方式进行处理,因为mongo是正确的,因为我要它查找与id匹配的文档,然后将它传递给它找到两个匹配的ID并将其投放。
Am i almost breaking it's functionality by asking it to do something different? 我是否通过要求它做一些不同的事情来破坏它的功能? Other options?
还有其他选择吗? Wrap it up in a for each in node and query each id manually and push to an array?
将其包装在每个in节点的a中,然后手动查询每个id并推送到数组?
Get the prizes for specific user.
获取特定用户的奖品。
$unwind
and $group
to count no of prizes followed by $lookup
to get prizes fields in 3.4. $unwind
和$group
不计算奖品数,然后$lookup
获取3.4中的奖品字段。
User.aggregate([
{"$match":{"_id":mongoose.Types.ObjectId(userid)}},
{"$unwind":"$prizes"},
{"$group":{"_id":"$prizes","count":{"$sum":1}}},
{"$lookup":{
"from":"prizes", // name of the prize collection
"localField":"_id",
"foreignField":"_id",
"as":"prizes"
}},
{"$addFields":{"prizes":{"$arrayElemAt":["$prizes",0]}}}
])
Get both the user and prizes.
获得用户和奖品。
Use $lookup
followed by $map
to keep the fields from lookup and use $filter
with $size
to count the no of prizes for each id in 3.4. 使用
$lookup
和$map
来阻止字段查找,并使用$filter
和$size
来计算3.4中每个id的奖品数量。
Something like 就像是
User.aggregate([
{"$match":{"_id":mongoose.Types.ObjectId(userid)}},
{"$lookup":{
"from":"prizes", // name of the prize collection
"localField":"prizes",
"foreignField":"_id",
"as":"prizeinfo"
}},
{"$addFields":{
"prizeinfo":{
"$map":{
"input":"$prizeinfo",
"as":"pi",
"in":{
"title":"$$pi.title",
"content":"$$pi.content",
"count":{
"$size":{
"$filter":{
"input":"$prizes",
"as":"p",
"cond":{"$eq":["$$pi._id","$$p"]}
}
}
}
}
}
}
}}
])
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