如何通过使用Mongoose MongoDB 2.6插入子文档中数组中的特定位置 [英] How to insert to the certain position in the array in the subdocument by using Mongoose an MongoDB 2.6

问题描述

A great explanation of how to use new $position operator of Mongodb 2.6 by using Mongoose was given in the answer to my question. The suggested solution works perfect for simple arrays. If array is in subdocument or each element of array is array the suggested solution doesn't work. I mean something like this:

List.collection.update(
{/*....*/},
{ "$push": {
    "subdocument.list": {
      "$each": [ 1, 2, 3 ],
      "$position": 0 }
    }
},function(err,NumAffected) {
  console.log("done");

});

List.collection.update(
{/*....*/},
{ "$push": {
    "list1.$.list2": {
      "$each": [ 1, 2, 3 ],
      "$position": 0 }
    }
},function(err,NumAffected) {
  console.log("done");

});

推荐答案

不确定问题出在哪里:

db.list.insert({ "list": { "sub": [4] } })
db.list.update(
    {},
    { "$push": { "list.sub": { "$each": [1,2,3], "$position": 0 } } }
)

{ "list" : { "sub" : [ 1, 2, 3, 4 ] } }

因此可以正常工作.

对于另一个示例:

db.list.insert({
    outer: [
       {
           key: "a", 
           inner: [4]
       },
       {
           key: "b", 
           inner: [4]
       }
   ]
})

db.list.update(
    { "outer.key": "b" },
    { "$push": { 
        "outer.$.inner": { 
            "$each": [1,2,3], "$position": 0 
        }
    }}
)

再次达到预期:

{
    "outer" : [
            {
                    "key" : "a",
                    "inner" : [
                            4
                    ]
            },
            {
                    "key" : "b",
                    "inner" : [
                            1,
                            2,
                            3,
                            4
                    ]
            }
    ]
}

已经解释了与特定驱动程序的交互，因此数据中必须有一些不同之处，但是如果是这样，则这些语句无效.

The interaction with specific drivers was already explained so there must be something different in the data, but if so then those statements are not valid.

使用猫鼬也是一样:

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

mongoose.connect('mongodb://localhost/nodetest');

var listSchema = new Schema({

});

var List = mongoose.model( "List", listSchema );
var Other = mongoose.model( "Other", listSchema );

  List.collection.update(
    {},
    { "$push": {
    "list.sub": {
      "$each": [ 1, 2, 3 ],
      "$position": 0 }
    }
    },function(err,NumAffected) {
      console.log("done");

    }
  );


  Other.collection.update(
    { "outer.key": "b" },
    { "$push": {
        "outer.$.inner": {
            "$each": [ 1, 2, 3 ],
            "$position": 0
        }
    }},function(err,NumAffected) {
      console.log("done2")
    }
  );

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