我正在为一个新项目设计数据库结构，而且我对 MongoDB 很陌生，显然是 Mongoose。
我已经阅读了 Mongooses人口文档，其中它具有一对多的关系，一个Person文档对多个Story文档，但让我感到困惑的部分是，而不是Story引用Person它所属的文档的文档，Person架构有它设置所以它有一系列Story它“拥有”的文件。
我正在设置与此非常相似的东西。Story但我一直认为在创建新文档以拥有Person文档 ID时会更容易。但也许那只是因为我更熟悉使用连接的 MySQL 关系。
如果这是最好的方法（我确信它是，因为它在文档中），当创建新文档时，更新它所属Story的相关文档中的故事数组的最佳方法是什么？People我查看但找不到任何更新现有文档以添加对其他文档的引用（或为此删除它们）的示例
我确信这是一个我刚刚忽略的简单解决方案，但任何帮助都会很棒。谢谢！
参考人口，这里从猫鼬中提取一个例子。
var mongoose = require('mongoose')
, Schema = mongoose.Schema
var personSchema = Schema({
_id : Schema.Types.ObjectId,
name : String,
age : Number,
stories : [{ type: Schema.Types.ObjectId, ref: 'Story' }]
});
var storySchema = Schema({
_creator : { type: Schema.Types.ObjectId, ref: 'Person' },
title : String,
fans : [{ type: Schema.Types.ObjectId, ref: 'Person' }]
});
var Story = mongoose.model('Story', storySchema);
var Person = mongoose.model('Person', personSchema);
因此，有关Story模型商店的示例Person._id在Story._creator. 当你找到一个 的文档时Story，你可以使用方法来定义你想要同时检索模型中的populate()哪个属性，例如：Person
Story.findOne({_id: 'xxxxxxx'}).populate('person', 'name age').exec(function(err, story) {
console.log('Story title: ', story.title);
console.log('Story creator', story.person.name);
});
我相信这就是你要找的。否则，您可以改用嵌套集合。
之前对这个问题的回答很有帮助，但查看更详细的代码可能会很有用。下面的代码来自我的应用程序的 Express.js 后端。我的应用程序允许用户撰写评论。在查询用户时，我会返回用户所做的所有评论。
user_model.js
import mongoose, { Schema } from 'mongoose';
const UserSchema = new Schema({
firstname: String,
lastname: String,
username: { type: String, unique: true },
reviews: [{ type: Schema.Types.ObjectId, ref: 'Review' }],
}, {
toJSON: {
virtuals: true,
},
});
const UserModel = mongoose.model('User', UserSchema);
export default UserModel;
review_model.js
import mongoose, { Schema } from 'mongoose';
const ReviewSchema = new Schema({
body: String,
username: String,
rating: Number,
}, {
toJSON: {
virtuals: true,
},
});
const ReviewModel = mongoose.model('Review', ReviewSchema);
export default ReviewModel;
review_controller.js
// . . .
export const createReview = (req, res) => {
const review = new Review();
review.username = req.body.username;
review.rating = req.body.rating;
review.body = req.body.body;
review.save()
.then((result) => {
User.findOne({ username: review.username }, (err, user) => {
if (user) {
// The below two lines will add the newly saved review's
// ObjectID to the the User's reviews array field
user.reviews.push(review);
user.save();
res.json({ message: 'Review created!' });
}
});
})
.catch((error) => {
res.status(500).json({ error });
});
};
user_controller.js
export const createUser = (req, res) => {
const user = new User();
user.username = req.body.username;
user.email = req.body.email;
user.save()
.then((result) => {
res.json({ message: 'User created!', result });
})
.catch((error) => {
res.status(500).json({ error });
});
};
// . . .
// returns the user object associated with the username if any
// with the reviews field containing an array of review objects
// consisting of the reviews created by the user
export const getUser = (req, res) => {
User.findOne({ username: req.params.username })
.populate('reviews')
.then((result) => {
res.json(result);
})
.catch((error) => {
res.status(500).json({ error });
});
};
正如人口文件所说
var aaron = new Person({ _id: 0, name: 'Aaron', age: 100 });
aaron.save(function (err) {
if (err) return handleError(err);
var story1 = new Story({
title: "Once upon a timex.",
_creator: aaron._id // assign the _id from the person
});
story1.save(function (err) {
if (err) return handleError(err);
// thats it!
});
//then add story to person
aaron.stories.push(story1);
aaron.save(callback);
});
这是创建一对多关系的好方法。
const mongoose = require("mongoose");
const Comment = mongoose.model(
"Comment",
new mongoose.Schema({
username: String,
text: String,
createdAt: Date
})
);
module.exports = Comment;
const mongoose = require("mongoose");
const Tutorial = mongoose.model(
"Tutorial",
new mongoose.Schema({
title: String,
author: String,
images: [],
comments: [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Comment"
}
]
})
);
module.exports = Tutorial;
const createComment = function(tutorialId, comment) {
return db.Comment.create(comment).then(docComment => {
console.log("\n>> Created Comment:\n", docComment);
return db.Tutorial.findByIdAndUpdate(
tutorialId,
{ $push: { comments: docComment._id } },
{ new: true, useFindAndModify: false }
);
});
};
一种或两种方式的关系
您可能会考虑另一种可能性：您真的需要双向关联吗？或者只存储_creator在 each 中就足够了Story。并且不要存储for list of storieseach Person。仍然可以在搜索中查询故事列表：
let allStoriesOfOneCreator = Stories.find({_creator: person._id});
最后，这取决于您的应用程序的要求。您多久需要一次创作者的故事？
// 如果你是类型脚本用户，那么：
import mongoose from 'mongoose';
interface PromotionAttrs {
price: number;
startDate: Date;
endDate: Date;
}
export interface PromotionDoc extends mongoose.Document {
price: number;
startDate: string;
endDate: string;
}
interface PromotionModel extends mongoose.Model<PromotionDoc> {
build(attrs: PromotionAttrs): PromotionDoc;
}
const promotionSchema = new mongoose.Schema({
price: {
type: Number,
},
startDate: {
type: mongoose.Schema.Types.Date,
},
endDate: {
type: mongoose.Schema.Types.Date,
},
});
promotionSchema.statics.build = (attrs: PromotionAttrs) => {
return new Promotion(attrs);
};
const Promotion = mongoose.model<PromotionDoc, PromotionModel>(
'Promotion',
promotionSchema
);
export { Promotion };
import mongoose from 'mongoose';
import { PromotionDoc } from './promotion';
interface ProductAttrs {
name: string;
promotions?: PromotionDoc[];
}
interface ProductModel extends mongoose.Model<ProductDoc> {
build(attrs: ProductAttrs): any;
}
interface ProductDoc extends mongoose.Document {
name: string;
promotions?: PromotionDoc[];
}
const productSchema = new mongoose.Schema({
promotions: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'Promotion',
},
],
});
productSchema.statics.build = (attrs: ProductAttrs) => {
return new Product(attrs);
};
const Product = mongoose.model<ProductDoc, ProductModel>(
'Product',
productSchema
);
export { Product };
const product = await Product.findById(productId);
if (!product) {
throw new NotFoundError();
}
const promotion = Promotion.build({
price,
startDate,
endDate,
});
await promotion.save();
product.promotions?.push();
await product.save();