发布时如何在http语句中使用object_id引用另一个模型？ （蒙戈数据库）

Question

I'm using a mongodb to create the REST API for an express app with node.js.

I created three different schemes that are somehow related to each other eg a book was written by an author and published by a publisher. Here is the scheme for the book.

const mongoose = require('mongoose')

const bookSchema = new mongoose.Schema({

    title: {
        type: String,
        required: true

    }, 
    author: {
        type: {type: mongoose.Schema.Types.ObjectId, ref: 'Author'},

    },
    publisher: {
        type: {type: mongoose.Schema.Types.ObjectId, ref: 'Publisher'},

    },
    isbn: {
        type: String,
        required: true

    },

})

module.exports = mongoose.model('Book', bookSchema)

Each of those schemes has an id, but I'm using the default id that is generated when posting an object.

Here is a part of the route-file .

//Creating one Book
router.post('/', async (req, res) => {
    const book = new Book({
        title: req.body.title,
        author: req.body.author.findById,
        publisher: req.body.publisher.findById,
        isbn: req.body.isbn
    })

    try {
        const newBook = await book.save()
        res.status(201).json(newBook)
    } catch {
        res.status(400).json({message: err.message})
    }
})

I am using a .rest-file for testing .

###
POST http://localhost:3000/books
Content-Type: application/json

{
    "title" : "test",
    "author" : "615c429dfe31a3863b6ebc8e", //object_id of an author in the db
    "publisher" : "615f3daf330081bcd5010861", //object_id of a publisher in the db
    "isbn" : "1234"
}

When I run this statement it will just create an object containing the object_id, a title and an isbn. The author and the publisher are left out. I did not set author and publisher as required in the scheme because it would throw an error (failed to cast string to object_id). I already tried that.

Can anyone please tell me how to avoid this casting error? I already googled and watched tutorials, but i did not find anything, yet.

Thank you.

Answer 1

There is difference between Mongoose and MongoDB native driver . Mongoose will automatically convert(Typecast) into Type defined in schema.

Your schema looks fine, you just need to change it like

//Creating one Book
router.post('/', async (req, res) => {
    const book = new Book({
        title: req.body.title,
        author: req.body.author,
        publisher: req.body.publisher,
        isbn: req.body.isbn
    })

    try {
        const newBook = await book.save()
        res.status(201).json(newBook)
    } catch {
        res.status(400).json({message: err.message})
    }
})