将 MongoDB 中的多个值与 pymongo 中的一个查询匹配

Question

我有一个集合测试，它具有以下值，我必须根据“值”字段从中获取文档，我可以从下面的给定查询中轻松获取。

db.getCollection('test').find({"value" : 100})

但真正的问题是我有“值”字段列表，例如 [100,104,200152,.......] 这个列表可能真的很长，我希望我的结果采用以下给定格式，以减少 mongo 查询的数量，因为这需要太多时间，如果包含“值”的列表太大，那么我必须执行多个 mongo 查询来获取所有的记录。

{100:[
    /* 1 */

    {
        "_id" : "C1",
        "value" : 100,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }

    /* 2 */
    {
        "_id" : "C2",
        "value" : 100,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }

    /* 3 */
    {
        "_id" : "C3",
        "value" : 100,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }

    /* 4 */
    {
        "_id" : "C4",
        "value" : 100,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }

    /* 5 */
    {
        "_id" : "CO",
        "value" : 100,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }

    /* 6 */
    {
        "_id" : "DD",
        "value" : 100,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }

    /* 7 */
    {
        "_id" : "EX",
        "value" : 100,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }],

104:

    [{
        "_id" : "AU",
        "value" : 104,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }],
200152:

    [
    {
        "_id" : "GenFile",
        "value" : 200152,
        "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
        "timetaken" : 3.0
    }
    ]

数据库

/* 1 */
{
    "_id" : "AU",
    "value" : 104,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 2 */
{
    "_id" : "C1",
    "value" : 100,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 3 */
{
    "_id" : "C2",
    "value" : 100,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 4 */
{
    "_id" : "C3",
    "value" : 100,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 5 */
{
    "_id" : "C4",
    "value" : 100,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 6 */
{
    "_id" : "CO",
    "value" : 100,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 7 */
{
    "_id" : "DD",
    "value" : 100,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 8 */
{
    "_id" : "EX",
    "value" : 100,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 9 */
{
    "_id" : "GS_SEG",
    "value" : 124755350,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

/* 10 */
{
    "_id" : "GenFile",
    "value" : 200152,
    "lastUpdatedTime" : ISODate("2019-11-04T00:00:00.000Z"),
    "timetaken" : 3.0
}

Answer 1

您可以使用以下聚合为您完成工作。但是，它会将值字段 100,104 作为字符串而不是数字（我必须使用 toString 运算符，否则会出错）。

db.collection.aggregate([
  {
    $group: {
      _id: "$value",
      root: {
        $push: "$$ROOT"
      }
    }
  },
  {
    $project: {
      k: {
        $toString: "$_id"
      },
      v: "$root",
      _id: 0
    }
  },
  {
    $group: {
      _id: null,
      x: {
        $push: "$$ROOT"
      }
    }
  },
  {
    $project: {
      _id: 0,
      x: {
        $arrayToObject: "$x"
      }
    }
  },
  {
    $replaceRoot: {
      newRoot: "$x"
    }
  }
])

以下将是输出：

[
  {
    "1.24755e+08": [
      {
        "_id": "GS_SEG",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 1.2475535e+08
      }
    ],
    "100": [
      {
        "_id": "C1",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 100
      },
      {
        "_id": "C2",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 100
      },
      {
        "_id": "C3",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 100
      },
      {
        "_id": "C4",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 100
      },
      {
        "_id": "CO",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 100
      },
      {
        "_id": "DD",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 100
      },
      {
        "_id": "EX",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 100
      }
    ],
    "104": [
      {
        "_id": "AU",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 104
      }
    ],
    "200152": [
      {
        "_id": "GenFile",
        "lastUpdatedTime": ISODate("2019-11-04T00:00:00Z"),
        "timetaken": 3,
        "value": 200152
      }
    ]
  }
]

Answer 2

您正在朝着正确的方向搜索，您将希望阻止您的代码将大部分时间花在网络请求上。 pymongo $in 运算符选择字段值等于指定数组中任何值的文档。

在你的情况下，它看起来像这样：

# Set or build a list of the values
list_with_values =  [100, 104, 200152]

# Make one call to the DB, asking for all of the matching records.
result = db.getCollection('test').find({"value" : {"$in": list_with_values})

关于$in 操作符如何工作的进一步参考：http://docs.mongodb.org/manual/reference/operator/query/in/