[英]How to populate an array of model instances inside a subdocument? MongoDB Mongoose
我有一个嵌套为数组的子文档。 在该子文档中,我引用了其他模型。 使用.Find
和.Populate
方法,我可以接收子文档中引用的单个模型的整个对象(请查看下面的停止),但不能接收模型实例数组、事实/建议。 对于事实/建议,我收到一组对象_ids
。 我可能只需要那些_ids
并进行另一个查询,但这看起来很混乱。
有没有办法填充数组? 我需要使用 Aggregate + $lookup 吗? 是否有更多的 Mongo 方法来重构架构以简化这一点?
谢谢大家和任何帮助!
我的子文档名为 TourStop:
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const TourStopSchema = new Schema({
stop: {
type: Schema.Types.ObjectId,
ref: 'Stop',
required:[true, 'must have a Stop'],
},
mandatory: {
type:Boolean,
default: false
},
check_in_time: {
type: Number,
default: 0
},
order: {
type:Number,
required: [true, 'Must have an order']
},
facts: [{
type: Schema.Types.ObjectId,
ref: 'Fact'
}],
recommendations: [{
type: Schema.Types.ObjectId,
ref: 'Recommendation'
}]
});
module.exports = TourStopSchema;
TourStops 住在 Tour 内:
const mongoose = require('mongoose');
const TourStopSchema = require('../subdocs/tour_stop');
const Schema = mongoose.Schema;
const tourSchema = new Schema({
name: {
type:String,
required:[true,'Name is required!'],
unique: true
},
city: {
type: String,
required: [true, 'City is required!']
},
tourStops:[TourStopSchema]
});
const Tour = mongoose.model('Tour', tourSchema);
module.exports = Tour;
Stop
Schema 填充得很好。
const mongoose = require('mongoose');
const LocationSchema = require('../subdocs/location');
const ImageSchema = require('../subdocs/image');
const Schema = mongoose.Schema;
const stopSchema = new Schema({
name:{
type: String,
required:[true,'Must have a name!']
},
location:LocationSchema,
categories: {
type: [String],
default:[]
},
images:{
type:[ImageSchema],
default:[]
}
});
const Stop = mongoose.model('Stop', stopSchema);
module.exports = Stop;
以及未正确填充的事实架构,而是返回带有 _ids 的字符串数组
事实:
const mongoose = require('mongoose');
const ImageSchema = require('../subdocs/image');
const Schema = mongoose.Schema;
const factSchema = new Schema({
stop: {
type: Schema.Types.ObjectId,
ref:'Stop',
required:[true, 'A Fact must have a Stop!'],
},
description: {
type: String,
required: [true,'A Fact must have a description!']
},
images: {
type:[ImageSchema],
default:[]
}
});
const Fact = mongoose.model('Fact', factSchema);
module.exports = Fact;
我正在运行测试以检查模式是否正确连接以检索 TourStop 的所有属性:
it('saves a full relation graph', (done) => {
User.findOne({ first_name: 'Dean' })
.populate({
// in that user find the tours property and load up all tours
path: 'tours',
// inside of all those tours, find the tourstops property and load all associated stops
populate: {
path: 'tour_stops.facts',
model: 'Fact'
},
populate: {
path: 'tour_stops.stop',
model: 'Stop'
}
})
// .populate('tours.tour_stops[0].facts')
.then((user) => {
// console.log(user.tours[0].tour_stops[0].stop);
console.log(user.tours[0].tour_stops[0]);
// console.log(Array.isArray(user.tours[0].tour_stops[0].facts))
assert(user.first_name === 'Dean' );
assert(user.tours.length === 1);
assert(user.tours[0].name === "Awesome New Tour");
assert(user.tours[0].tour_stops[0].stop.name === 'Jaffa Clock Tower');
// assert(user.tours[0])
// assert(user.blogPosts[0].title === 'JS is Great');
// assert(user.blogPosts[0].comments[0].content === 'Congrats on great post!' );
// assert(user.blogPosts[0].comments[0].user.name === 'Joe' )
done();
})
})
您可以使用以下代码来填充游览、停靠点、事实和建议。 注意在model
属性中,我们不应该给出字符串值,而是模型本身。 所以你需要将它们导入到你的代码中。
User.findOne({ first_name: "Dean" })
.populate({
path: "tours",
populate: {
path: "tourStops.stop",
model: Stop
}
})
.populate({
path: "tours",
populate: {
path: "tourStops.facts",
model: Fact
}
})
.populate({
path: "tours",
populate: {
path: "tourStops.recommendations",
model: Recommendation
}
})
.then(user => {
console.log(user);
});
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