Question

注意：与<{3}}问有关，因为它们不包含数组过滤器匹配项。 < / p>

我有以下查询：

db.UserNotifications.updateOne(
    {_id:ObjectId("5c5c39e94c9d4404d4577e94")}, 
    {$set:{
        "Notifications.$[match].Group.ActualUnreadCount": 50,
        "Notifications.$[match].Group.UnreadCountSnapshot": "Notifications.$[match].Group.ActualUnreadCount"
    }},
    {arrayFilters:[{
        "match.Group.Id": "some-id"
    }]});

现在，我要做的是将数组中匹配项的UnreadCountSnapshot的值设置为相同匹配项的ActualUnreadCount的值。

相反，UnreadCountSnapshot仅设置为字符串"Notifications.$[match].Group.ActualUnreadCount"。

关于如何实现这一点的任何想法？

以下是集合中的示例文档：

{
    "_id": {
        "$oid": "5c5c39e94c9d4404d4577e94"
    },
    "Notifications": [{
        "Object": {
            "_id": "5e3967cc9fc5720001d7100f",
            "Type": "Transaction"
        },
        "Change": {
            "Verb": "Create",
            "TimeUtc": {
                "$date": "2020-02-04T12:47:08.796Z"
            },
            "Actors": []
        },
        "Group": {
            "TotalCount": 2,
            "ActualUnreadCount": 50,
            "UnreadCountSnapshot": 23,
            "ReadTimeUtc": {
                "$date": "2020-08-26T10:24:32.602Z"
            },
            "ViewTimeUtc": {
                "$date": "2020-08-26T10:24:32.602Z"
            }
        }
    }],
    "LastNotificationTimeUtc": {
        "$date": "2019-02-21T10:18:57.456Z"
    },
    "LastDeletedNotificationTimeUtc": {
        "$date": "2020-08-26T10:24:30.374Z"
    }
}

Answer 1

arrayFields不允许将任何参考字段值分配给另一个字段，您可以使用MongoDB v4.2中的update document with aggregation pipeline，

db.UserNotifications.updateOne(
  { _id: ObjectId("5c5c39e94c9d4404d4577e94") },
  [{
    $set: {
      Notifications: {
        $map: {
          input: "$Notifications",
          in: {
            $mergeObjects: [
              "$$this",
              {
                $cond: [{
                    $eq: [
                      "$$this.Object._id",
                      "5e3967cc9fc5720001d7100f" // some id
                    ]
                  },
                  {
                    Group: {
                      $mergeObjects: [
                        "$$this.Group",
                        {
                          ActualUnreadCount: 50, // add update number
                          UnreadCountSnapshot: "$$this.Group.ActualUnreadCount"
                        }
                      ]
                    }
                  },
                  {}
                ]
              }
            ]
          }
        }
      }
    }
  }]
)

Playground

将arrayFilter的字段设置为匹配另一个字段的值

1 个答案: