無法填充物件陣列-有解無憂

編輯添加了 mongoose.model。

我對 mongodb 和 mongoose 還很陌生。我無法在貓鼬中向作者填充書籍。任何人都可以幫助我嗎？這是我的代碼。我洗掉了不必要的欄位

const authorSchema = mongoose.Schema({
    _id:{
        type: String,
        required: true,
        unique: true,
        trim: true
    },
    name: {
        type: String,
        required: true,
        trim: true
    },
    books: [{
        type: String,
        ref: "Book"
    }]
}, {_id:false})

const Author = mongoose.model('Author', authorSchema)

module.exports = {Author}

我的書籍架構如下所示

const bookSchema = mongoose.Schema({
    _id:{
        type:String,
        required:true,
        unique:true,
        trim: true
    },
    name: {
        type: String,
        required: true,
        trim: true,
        unique: true
    },
    description:{
        type: String,
        trim: true,
        default: 'No description specified'
    },
    datePublished: {
        type: Date,
        trim: true,
        default: '01/01/2001'
    },
    author:{
        type: String,
        ref: 'Author',
        required: true
    }
}, {_id:false})
const Book = mongoose.model('Book', bookSchema)

module.exports = {Book}

這是將它們填充在一起的路線

AuthorRouter.get('/authors/:id', async(req, res)=>{
    const authorID = req.params.id
    try {
        const author = await Author.findById(authorID)
        try {
            const populated = await author.populate({path: 'books.book', select: 'name description -_id'})
            console.log(populated);
            res.status(201).send(populated)
        } catch (e) {
            res.status(401).send(`${e}\n Unable to populate categories`)
        }
        
    } catch (error) {
        res.status(401).send('Unable to find author')
    }
})

輸出是空的書籍陣列：

{
    "_id": "123",
    "name": "testuser",
    "books": [],
    "__v": 0
}

uj5u.com熱心網友回復：

填充 refs 陣列的作業方式與單個 ref 相同。只需在查詢上呼叫 populate 方法，就會回傳一個檔案陣列來代替原始_id的。

在你的情況下，這將是：

const populated = await author.populate({path: 'books', select: 'name description -_id'});

uj5u.com熱心網友回復：

嘿，我已經修改了你的代碼，嘗試使用這個

這是您的作者架構檔案

const Schema = mongoose.Schema;
const authorSchema = mongoose.Schema({
    _id:{
        type: String,
        required: true,
        unique: true,
        trim: true
    },
    name: {
        type: String,
        required: true,
        trim: true
    },
    books: [{
        type: Schema.Types.ObjectId,
        ref: "bookSchema"
    }]
}, {_id:false})

const Author = mongoose.model('Author', authorSchema)

module.exports = {Author}

這是你的路線


AuthorRouter.get('/authors/:id', async(req, res)=>{
    const authorID = req.params.id
    try {
        const author = await Author.findById(authorID)
        try {
            const populated = await author.find().populate('books');
            console.log(populated);
            res.status(201).send(populated)
        } catch (e) {
            res.status(401).send(`${e}\n Unable to populate categories`)
        }
        
    } catch (error) {
        res.status(401).send('Unable to find author')
    }
})

轉載請註明出處，本文鏈接：https://www.uj5u.com/qita/399954.html

標籤：节点.js MongoDB 表达猫鼬

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