猫鼬与第三级嵌套字段值进行比较

Question

我有以下收藏：

我想从collection1一直查找到collection 3和collection 4，以便在一个查询中比较名称。

示例：

collection1.find({
    collection2.collection3.name: req.body.name3,
    collection2.collection4.name: req.body.name4
}).exec()

Answer 1

您需要使用查找，展开和匹配，这是未经测试的问题解决方案

 Model.aggregate([
     {
         $match: {
             _id: req.params.id
             // for object id use
             // _id: mongoose.Types.ObjectId(req.params.id)
         }
     },
        {
          $lookup: {
            from: "collection2",
            localField: "collection2",
            foreignField: "_id",
            as: "Collection2"
          }
        },
        {
            $unwind: "$ColelctionTwo"
        },
        {
          $lookup: {
            from: "collection3",
            localField: "CollectionTwo.collection3",
            foreignField: "_id",
            as: "Collection3"
          }
        },
        {
          $lookup: {
            from: "collection4",
            localField: "CollectionTwo.collection4",
            foreignField: "_id",
            as: "Collection4"
          }
        }
      ]).exec(function(err, result) {
          if(err) {
              // handle here
          }
          if(result) {
              // do something here...
          }
      }

Answer 2

您可以使用mongodb聚合框架的$lookup或$graphlookup阶段进行多集合查询。汇总https://mongoosejs.com/docs/api.html#Aggregate的猫鼬文档 您无法对多馆藏查询进行简单的查找查询。