我的猫鼬关系有什么问题？答案

【问题标题】：What is wrong with my Mongoose Relationship?我的猫鼬关系有什么问题？
【发布时间】：2019-11-24 05:39:27
【问题描述】：

我正在学习猫鼬关系并陷入这个问题......有人告诉我我错在哪里......？有没有更好的方法来做到这一点..？

Employee.js

const mongoose = require("mongoose");
const { departmentSchema, addDepartment } = require("./Departments");

const schema = new mongoose.Schema();

const employeeModel = mongoose.model("Employee", {
  Name: { type: String, required: true, minlength: 5, maxlength: 50 },
  Department: departmentSchema
});

async function addEmployee(Employee, Department, Language, Framework) {
  const result = await new employeeModel({
    ...Employee,
    Department: addDepartment(Department, Language, Framework)
  });
  return await result.save();
}

Department.js

const mongoose = require("mongoose");
const { languageSchema, addLanguage } = require("./Language");

const departmentSchema = new mongoose.Schema({
  Depart: { type: String, required: true, minlength: 5, maxlength: 50 },
  Languages: languageSchema
});

const DepartmentModel = mongoose.model("Department", departmentSchema);

async function addDepartment(Department, Language, Framework) {
  const result = await new DepartmentModel({
    ...Department,
    Languages: addLanguage(Language, Framework)
  });
  return await result.save();
}

module.exports = {
  departmentSchema,
  addDepartment
};

Language.js

const mongoose = require("mongoose");
const { frameworkSchema, addFramework } = require("./Frameworks");

const languageSchema = new mongoose.Schema({
  Language: { type: String, required: true },
  Framework: [frameworkSchema]
});

const languageModel = mongoose.model("Language", languageSchema);

async function addLanguage(Language, Framework) {
  const result = await new languageModel({
    ...Language,
    Framework: addFramework(Framework)
  });
  return await result.save();
}

module.exports = {
  languageSchema: languageSchema,
  addLanguage
};

Framework.js

const mongoose = require("mongoose");

const frameworkSchema = new mongoose.Schema({
  Name: { type: String, required: true, minlength: 4, maxlength: 50 },
  Version: { type: String, required: true, minlength: 1, maxlength: 50 }
});

const frameworkModel = mongoose.model("Framework", frameworkSchema);

async function addFramework(Framework) {
  const result = await new frameworkModel(...Framework);
  return await result.save();
}

module.exports = {
  frameworkSchema,
  addFramework
};

Framework.js 出错

Found non-callable @@iterator

我想做的是

员工 ->
姓名
部门->
出发
语言->
语言名称
框架->
框架名称
框架版本

Every -> 代表一个新的对象（集合）

我知道对于像我这样的新手来说这有点复杂...... 我是 MySql 数据库用户，我很喜欢它，但现在我正在尝试掌握 NoSql...

提前谢谢:)

【问题讨论】：

标签： node.js mongodb mongoose nosql relationship

【解决方案1】：

我给你看一个例子：假设您已经有这样的 employSchema：

const {Schema} = mongoose;
const employeeModel = mongoose.model("Employee", new Schema({
  Name: { type: String, required: true, minlength: 5, maxlength: 50 },
  Department: {type: Schema.Types.ObjectId, ref: "Department"}
}));

在上面的模型中，我使用 ref 属性通过 ObjectId 连接到 Department 模型（即Department集合中的“_id”属性)。

例如：您将像这样创建一个新的employeeModel：

let newEmployee = new employeeModel("Employee Name", Department ID here).

您绝对会做相反的事情或为他人做事。您需要使用 .populate() 函数来查询数据库。示例：

employModel.find({}).populate("Department").exec(callback what you want to do);

您可以阅读官方文档：https://mongoosejs.com/docs/populate.html

【讨论】：

感谢 Hai Huynh Ngoc 的回复...我熟悉您上面讨论的方法（规范化）...我正在尝试嵌入文档（去规范化）

【解决方案2】：

一如既往地解决了错误：p

错误是因为 Framework.js 中的扩展运算符 (...)

const result = await new frameworkModel(...Framework);

如果有人能告诉我这样做的更好方法，我们将不胜感激。

谢谢大家。

【讨论】：