Mongo Shell 更新嵌套的文档数组

问题描述

我尝试将数组内文档的属性设置为大写。 这是 mongodb 游乐场的链接 https://mongoplayground.net/p/BTP_h3kqK_S

这是一个文档示例

  {
    "_id": ObjectId("5e786a078bc3b3333627341e"),"value": {
      "items": [
        {
          "itemName": "alpha305102992","itemNumber": ""
        },{
          "itemName": "beta305102630","itemNumber": "P5000"
        },{
          "itemName": "gamma305102633 ","itemNumber": ""
        }
      ]
    }
  }

我尝试将“itemName”设置为大写。

我想要的结果是：

  {
    "_id": ObjectId("5e786a078bc3b3333627341e"),"value": {
      "items": [
        {
          "itemName": "ALPHA305102992",{
          "itemName": "BETA305102630",{
          "itemName": "GAMMA305102633 ","itemNumber": ""
        }
      ]
    }
  }

解决方法

演示 - https://mongoplayground.net/p/geb1MRHXNyk

使用update-documents-with-aggregation-pipeline

db.collection.update({},[
  {
    $set: {
      value: {
        items: { // set item to loop only once
          $map: {
            input: "$value.items",// loop over items
            in: {
              $mergeObjects: [ // merge document
                "$$this",{ itemName: { $toUpper: "$$this.itemName" } } // change individual itemName to upper
              ]
            }
          }
        }
      }
    }
  }
])

---

聚合演示 - https://mongoplayground.net/p/9wtSkyjC88c

带有游乐场链接的演示 - https://mongoplayground.net/p/5J7Qz97gZoJ

使用 Playground 链接更新演示 - https://mongoplayground.net/p/8LHEuMakpFF

,

• $map 迭代 value.items 数组的循环
• 使用 itemName 将 $toUpper 转换为大写
• $mergeObjects 将当前对象与更新后的 itemName 字段合并

db.collection.update({},[{
    $set: {
      "value.items": {
        $map: {
          input: "$value.items",in: {
            $mergeObjects: [
              "$$this",{ itemName: { $toUpper: "$$this.itemName" } }
            ]
          }
        }
      }
    }
  }]
)

Playground