如何在将值插入数据库之前检查从 api 接收的数据中是否已存在值

Question

我很难尝试将从 api 接收到的数据写入数据库。我成功获取数据，然后必须将其写入 db。重点是检查引用是否已经存在于我的 collection 中。我正在处理的问题是每个值都被插入到我的 collection 中，与它是否存在无关。

 const { MongoClient } = require('mongodb')

 const mongoUrl = 'mongodb://localhost/kanye_quotes'

 async function connectToDb() {
      const client = new MongoClient(mongoUrl, { useNewUrlParser: true })
      await client.connect()
      db = client.db()
 }

 async function addQuote(data) {
 await connectToDb()
 try {
    const collection = db.collection('quotes')
    let quotes = [];
    quotes = await collection.find({}).toArray()

    if (quotes = []) { // I added this piece of code because if not check for [], no values will be inserted
        collection.insertOne(data, (err, result) => {
            if (err) {
                return
            }
            console.log(result.insertedId);
            return
        })
    }

    quotes.forEach(quote => {
        if (quote.quote !== data.quote) { // I compare received data with data in collection, it actually works fine(the comparison works as it supposed to)

            collection.insertOne(data, (err, result) => {
                if (err) {
                    return
                }
                console.log(result.insertedId);
            })
        } else console.log('repeated value found'); // repeated value gets inserted. Why?
    })
 }
  catch (err) {
    console.log(err)
 }
}

Answer 1

您好，最好在您的架构上设置 unique: true indexing。这样你就不会有重复的值。

如何在将值插入数据库之前检查从 api 接收的数据中是否已存在值

How to check if value already exists in the data received from api before inserting it into db

asynchronous

crud

mongodb

async-await