图书馆藏的mongodb设计和开发实例

developer.mozilla.org/en-US/docs/…

Web App 的 M组件开发

1 开发的第一步，当然是概念模型的设计
	L 业务对象的ER图
2 第二是，为所有的 业务对象数据模型 创建 mongoose 的文档格式（schema）定义
	L 一个对象，一个schema定义
3 为了更好的理解，我们可从反向——代码开发的角度看 这个过程 所需要的开发任务 （queries -> model -> schema -> connecting -> db setup） 	
	L 同时，看mongoose提供什么API 工具
4 从代码的角度，我们需要一个可以增加数据持久化（增删改查）的「JS对象」
	L 例如如下的，一个notes 数组，我们想取得所有note
	E  这个「JS对象」是个什么类型的对象？

export const renderNotes = async (req, res) => {
  const notes = await Note.find({ user: req.user.id })
    .sort({ date: "desc" })
    .lean();
  res.render("notes/all-notes", { notes });
};

5 为了取得文档（上面的集合）数据，我们得先创建一个 对象模型实例，例如 

let EmailModel = require('./email')

let msg = new EmailModel({
  email: 'ada.lovelace@gmail.com'
})

/express-locallibrary-tutorial  //the project root
  /models
    author.js
    book.js
    bookinstance.js
    genre.js

Author model (./models/author.js )

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

var AuthorSchema = new Schema(
  {
    first_name: {type: String, required: true, maxLength: 100},
    family_name: {type: String, required: true, maxLength: 100},
    date_of_birth: {type: Date},
    date_of_death: {type: Date},
  }
);

// Virtual for author's full name
AuthorSchema
.virtual('name')
.get(function () {
  return this.family_name + ', ' + this.first_name;
});

// Virtual for author's lifespan
AuthorSchema
.virtual('lifespan')
.get(function () {
  return (this.date_of_death.getYear() - this.date_of_birth.getYear()).toString();
});

// Virtual for author's URL
AuthorSchema
.virtual('url')
.get(function () {
  return '/catalog/author/' + this._id;
});

//Export model
module.exports = mongoose.model('Author', AuthorSchema);

Book

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

var BookSchema = new Schema(
  {
    title: {type: String, required: true},
    author: {type: Schema.Types.ObjectId, ref: 'Author', required: true},
    summary: {type: String, required: true},
    isbn: {type: String, required: true},
    genre: [{type: Schema.Types.ObjectId, ref: 'Genre'}]
  }
);

// Virtual for book's URL
BookSchema
.virtual('url')
.get(function () {
  return '/catalog/book/' + this._id;
});

//Export model
module.exports = mongoose.model('Book', BookSchema);

BookInstance

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

var BookInstanceSchema = new Schema(
  {
    book: { type: Schema.Types.ObjectId, ref: 'Book', required: true }, //reference to the associated book
    imprint: {type: String, required: true},
    status: {type: String, required: true, enum: ['Available', 'Maintenance', 'Loaned', 'Reserved'], default: 'Maintenance'},
    due_back: {type: Date, default: Date.now}
  }
);

// Virtual for bookinstance's URL
BookInstanceSchema
.virtual('url')
.get(function () {
  return '/catalog/bookinstance/' + this._id;
});

//Export model
module.exports = mongoose.model('BookInstance', BookInstanceSchema);

Genre model - challenge!

Open your ./models/genre.js file and create a schema for storing genres (the category of book, e.g. whether it is fiction or non-fiction, romance or military history, etc).

The definition will be very similar to the other models:

• The model should have a String SchemaType called name to describe the genre.
• This name should be required and have between 3 and 100 characters.
• Declare a virtual for the genre's URL, named url.
• Export the model.