Question

假设像这样的mongodb集合模式：

{
   "_id"         : ObjectId("5a5b2657a19692e18a3792ad"),
   "Toponym"     : "Climate station Stavenhagen",
   "Lat"         : 53.33333,
   "Lon"         : "13.99999",
   "SensorMaker" : "Hitachi",
   "SensorClass" : "Thermometer",
   "Dimension"   : "SoilTemperature_0.05mSensor1",
   "Gauge"       : "degC"
}

我想将完整的集合（~90k项目）更改为此，以符合最小的GeoJson：

{
  "_id"         : ObjectId("5a5b2657a19692e18a3792ad"),
  "Toponym"    : "Climate station Stavenhagen",
  "geometry"   : {
       "type"        : "Point", 
       "coordinates" : [53.33333, 13.99999]
       },
  "SensorMaker": "Hitachi",
  "SensorClass": "Thermometer",
  "Dimension"  : "SoilTemperature_0.05mSensor1",
  "Gauge"      : "degC"
}

我尝试使用此查询转换它，但无论我做什么，我都会收到类似的错误＆＃34;第5行：意外的字符串＆＃34;：

db.sensor_geo.aggregate([
{ '$group' : {
    '_id' : '$_id',
    'Toponym' : '$Toponym'
    'geometry': { 'type': 'Point', { $set : {"coordinates.$[]": [ {'$Lat', '$Lon'} ] }}},
    'SensorMaker' : '$SensorMaker',
    'SensorClass' : '$SensorClass',
    'Dimension'   : '$Dimension',
    'Gauge'       : '$Gauge'
   } 
}
]);

我应该使用$push代替$set，即使这也无处可去吗？我是否还必须为嵌套的Object创建一个ObjectID，这可能导致了这个问题？

Answer 1

您可以使用批量写入尝试以下聚合管道。

下面的聚合将Lat和Lon字段更改为具有批量更新的几何图形，以写入新的几何字段并删除Lat和Lon字段。

var bulk = db.getCollection("sensor_geo").initializeUnorderedBulkOp();
var count = 0;
var batch = 1;

db.getCollection("sensor_geo").aggregate([
{"$project":{
    "geometry":{
      "type":"Point", "coordinates":["$Lat", "$Lon"]
    }
}}]).forEach(function(doc){ 
    var _id = doc._id; 
    var geometry = doc.geometry; 
    bulk.find({ "_id" : _id }).updateOne(
      {
        $set: {"geometry":geometry},
        $unset: {"Lat":"", "Lon":""}
      }
   ); 
    count++;  
    if (count == batch) { 
        bulk.execute(); 
        bulk = db.getCollection("sensor_geo").initializeUnorderedBulkOp(); 
        count = 0;
    } 
});

if (count > 0) { 
    bulk.execute(); 
}

转换Mongodb架构，包括嵌套的Object

1 个答案: