MongoDB - 在ObjectId上聚合$匹配

Question

我有一个如下所示的架构:

var mongoose = require('mongoose');

module.exports = mongoose.model('Owner',{
    username: String,
    blocks: {type:mongoose.Schema.Types.ObjectId, ref: 'Block'},
});

我正在尝试运行查询以查看所有者是否具有对Block的id的引用.所有者有一个ObjectIds数组.当我运行db.owners.aggregate({$match: {username: 'example'}},{$unwind: "$blocks"},{$project: { _id : 1,blocks: 1}})它时返回:

{ "_id" : ObjectId("550d9dc64d9dc3d026fadfc7"), "blocks" : ObjectId("550dc117dc9605ab27070af7") }
{ "_id" : ObjectId("550d9dc64d9dc3d026fadfc7"), "blocks" : ObjectId("550dc123dc9605ab27070af8") }
{ "_id" : ObjectId("550d9dc64d9dc3d026fadfc7"), "blocks" : ObjectId("550dc12edc9605ab27070af9") }
{ "_id" : ObjectId("550d9dc64d9dc3d026fadfc7"), "blocks" : ObjectId("550dc157dc9605ab27070afa") }

我怎样才能匹配块ID？我试过db.publishers.aggregate({$match: {username: 'example'}},{$unwind: "$blocks"},{$project: { _id : 1,blocks: 1}},{$match : {"blocks._id" : '550dc157dc9605ab27070afa'}})但是那不起作用.

Answer 1

我认为你不需要聚合,你可以使用简单find()或findOne()查询:

var Mongoose = require('mongoose');
var ObjectId = Mongoose.Types.ObjectId;

Owner.findOne({ username: 'example', blocks: new ObjectId('550dc157dc9605ab27070afa') }, function (err, owner) {
   ...
});