在2个不同的字段中搜索值mongodb + node.js

Question

我是新手.但我尝试学习编写查询的最合理方法.

假设我收集的是;

{ 
    "id" : NumberInt(1), 
    "school" : [
        {
            "name" : "george", 
            "code" : "01"
        }, 
        {
            "name" : "michelangelo", 
            "code" : "01"
        }
    ], 
    "enrolledStudents" : [
        {
            "userName" : "elisabeth", 
            "code" : NumberInt(21)
        }
    ]
}
{ 
    "id" : NumberInt(2), 
    "school" : [
        {
            "name" : "leonarda da vinci", 
            "code" : "01"
        }
    ], 
    "enrolledStudents" : [
        {
            "userName" : "michelangelo", 
            "code" : NumberInt(25)
        }
    ]
}

我想列出一个key带有相应code值的a的出现.

举个例子key:michelangelo

为了找到密钥的出现,我写了两个不同的aggregation查询;

db.test.aggregate([
    {$unwind: "$school"},
    {$match : {"school.name" : "michelangelo"}},
    {$project: {_id: "$id", "key" : "$school.name", "code" : "$school.code"}}
])

和

db.test.aggregate([
    {$unwind: "$enrolledStudents"},
    {$match : {"enrolledStudents.userName" : "michelangelo"}},
    {$project: {_id: "$id", "key" : "$enrolledStudents.userName", "code" : "$enrolledStudents.code"}}
])

这两个查询的结果返回我想要的结果;

{ "_id" : 1, "key" : "michelangelo", "code" : "01" }
{ "_id" : 2, "key" : "michelangelo", "code" : 25 }

其中enrolledStudents一个是搜索,另一个是在school现场搜索.

这两个查询可以简化为更符合逻辑的查询吗？或者这是唯一的方法吗？

ps:我知道数据库结构不合逻辑,但我试图模拟.

编辑 我尝试用find编写查询.

db.test.find({$or: [{"enrolledStudents.userName" : "michelangelo"} , {"school.name" : "michelangelo"}]}).pretty()

但这会将整个文件归还为;

{
    "id" : 1,
    "school" : [
        {
            "name" : "george",
            "code" : "01"
        },
        {
            "name" : "michelangelo",
            "code" : "01"
        }
    ],
    "enrolledStudents" : [
        {
            "userName" : "elisabeth",
            "code" : 21
        }
    ]
}
{
    "id" : 2,
    "school" : [
        {
            "name" : "leonarda da vinci",
            "code" : "01"
        }
    ],
    "enrolledStudents" : [
        {
            "userName" : "michelangelo",
            "code" : 25
        }
    ]
}

Answer 1

蒙戈3.4

$match- 此阶段将保留所有school数组以及enrolledStudents至少一个与查询条件匹配的嵌入文档

$group- 此阶段会将所有school和enrolledStudents数组合并为_id组中每个数组的二维数组。

$project- 此阶段将匹配查询条件的数组和$filter带有新标签的数组。merge$mapvalues

$unwind- 此阶段将使阵列变平。

$addFields& $replaceRoot- 此阶段将添加id字段并将values数组提升到顶部。

db.collection.aggregate([
    {$match : {$or: [{"enrolledStudents.userName" : "michelangelo"} , {"school.name" : "michelangelo"}]}},
    {$group: {_id: "$id", merge : {$push:{$setUnion:["$school", "$enrolledStudents"]}}}},
    {$project: {
        values: {
              $map:
                 {
                   input: {
                            $filter: {
                                input: {"$arrayElemAt":["$merge",0]},
                                as: "onef",
                                cond: {
                                    $or: [{
                                        $eq: ["$$onef.userName", "michelangelo"]
                                    }, {
                                        $eq: ["$$onef.name", "michelangelo"]
                                    }]
                                }
                            }
                        },
                   as: "onem",
                   in: { 
                         key : { $ifNull: [ "$$onem.userName", "$$onem.name" ] },
                         code : "$$onem.code"}
                 }
            }
        }
    },
    {$unwind: "$values"},
    {$addFields:{"values.id":"$_id"}},
    {$replaceRoot: { newRoot:"$values"}}
])

响应样本

{ "_id" : 2, "key" : "michelangelo", "code" : 25 }
{ "_id" : 1, "key" : "michelangelo", "code" : "01" }

蒙戈 <= 3.2

将上述聚合的最后两个阶段替换为$project格式化响应。

{$project: {"_id": 0 , id:"$_id", key:"$values.key", code:"$values.code"}}

响应样本

{ "_id" : 2, "key" : "michelangelo", "code" : 25 }
{ "_id" : 1, "key" : "michelangelo", "code" : "01" }

您可以使用$redact代替$group&match并添加$projectwith$map来格式化响应。

$redact一次浏览一个文档级别并执行$$DESCEND匹配$$PRUNE标准。

唯一需要注意的是$ifNull在第一个文档级别中使用 for id，以便您可以$$DESCEND嵌入文档级别进行进一步处理。

db.collection.aggregate([
    {
        $redact: {
            $cond: [{
                $or: [{
                    $eq: ["$userName", "michelangelo"]
                }, {
                    $eq: ["$name", "michelangelo"]
                }, {
                    $ifNull: ["$id", false]
                }]
            }, "$$DESCEND", "$$PRUNE"]
        }
    },
    {
        $project: {
            id:1,
            values: {
              $map:
                 {
                   input: {$setUnion:["$school", "$enrolledStudents"]},
                   as: "onem",
                   in: { 
                         key : { $ifNull: [ "$$onem.userName", "$$onem.name" ] },
                         code : "$$onem.code"}
                 }
            }
        }
    },
    {$unwind: "$values"},
    {$project: {_id:0,id:"$id", key:"$values.key", code:"$values.code"}}
])