MongoDB递归、聚合、嵌套测试

1.递归测试

测试目标：递归查询某个用户的全部子用户。
测试环境：MongoDB 3.2.0

插入测试数据

db.categories.insert({_id: "MongoDB", parent: "Databases" } )
db.categories.insert({_id: "dbm", parent: "Databases" } )
db.categories.insert({_id: "Databases", parent: "Programming" } )
db.categories.insert({_id: "Languages", parent: "Programming" } )
db.categories.insert( { _id: "Programming", parent: "Books" } )
db.categories.insert( { _id: "Books", parent: null } )

读取Programming的后代

function findChildren(parent) {
     var myCursor = db.categories.find({"parent":parent});
     while(myCursor.hasNext()) {
          var myJsonString = tojson(myCursor.next());
          print(myJsonString);
          var myJsonObject = JSON.parse(myJsonString);
          findChildren(myJsonObject._id); 
     }
}
findChildren("Programming");

2.聚合测试

给定统计周期和设备列表，对设备数据进行统计。

db.car.insert({deviceId:'111111',fuelConsum:5,mileage:1000,createTime:"2011-10-29 0:0:1"})
db.car.insert({deviceId:'222222',fuelConsum:6,mileage:2000,createTime:"2012-10-29 0:0:1"})
db.car.insert({deviceId:'333333',fuelConsum:7,mileage:3000,createTime:"2013-10-29 0:0:1"})
db.car.insert({deviceId:'444444',fuelConsum:8,mileage:4000,createTime:"2014-10-29 0:0:1"})
db.car.insert({deviceId:'555555',fuelConsum:9,mileage:5000,createTime:"2015-10-29 0:0:1"})
db.car.insert({deviceId:'666666',fuelConsum:10,mileage:6000,createTime:"2016-10-29 0:0:1"})

统计平均油耗
统计周期：2012-2016年
统计设备列表：[“111111”, “222222”, “333333”, “444444”, “555555”]

var deviceList = ["111111","222222","333333", "444444", "555555"];
db.car.aggregate([
  {$match:{"$and":[
    {"createTime":{"$gt":"2012-1-1 0:0:0"}},
    {"createTime":{"$lt":"2016-12-31 0:0:0"}},
    {"deviceId":{$in:deviceList}}]}},
  {$group:{_id:null,avg_fuel:{$avg:"$fuelConsum"}}}
])