如果mongodb中存在相同的键，如何更新数据？

Question

我正在从CSV 文件插入数据，如果对象键相同，我想更新新价格，我使用csvtojson 解析CSV 文件和multer 用于文件上传。

CSV 文件包含 itemNumber、title 和 price 列

sample.csv

itemNumber,title,price
STY0047,Men Straight Fit Jeans,2500
STY0048,Men Straight Fit Jeans,2450
STY0049,Men Straight Fit Jeans,2550
STY0050,Men Straight Fit Jeans,3000
STY0048,Men Straight Fit Jeans,4000
STY002,Men Straight Fit Jeans,2550
STY0053,Men Straight Fit Jeans,3000
STY0054,Men Straight Fit Jeans,3000
STY0043,Men Straight Fit Jeans,4000

我的代码

router.post("/file-insert-data", upload, async function (req, res, next) {

  if (!req.file) {
    return res.status(400).send("no file found");
  }

  const results = await csv().fromFile(req.file.path);

  for (let obj in results ) {
      const csvData = new csvModel(results [obj])

      csvData.save((err, data) => {
        if(err) {
          return res.status(400).send("csv data is not inserted")
        }
        return res.status(201).send(data)
      })
    }
  
});

帮帮我谢谢

Answer 1

1. 尝试使用findOne 函数来检查元素是否已经存在（我假设itemNumber 是模型的关键）。
2. 如果没有，则创建csvModel 的新实例
3. 更新价格
4. 保存数据

router.post('/file-insert-data', upload, async function (req, res, next) {
  if (!req.file) {
    return res.status(400).send('no file found');
  }

  try {
    const results = await csv().fromFile(req.file.path);
    let updatedData = []; // Array to store the updated data
    for (const item of results) {
      const { itemNumber, title, price } = item;
      let csvData = await csvModel.findOne({ itemNumber });
      if (!csvData) {
        // Create new data if not present
        csvData = new csvModel();
        csvData.itemNumber = itemNumber;
        csvData.title = title;
      }
      // Update the price
      csvData.price = price;

      // Save the created / updated data
      await csvData.save();

      updatedData.push(csvData);
    }

    return res.status(201).send(updatedData);
  } catch (err) {
    return res.status(500).send('Error updating data');
  }
});

Answer 2

更新

在与 OP 合作后，这里是与原始问题一致的猫鼬友好版本。它突出了upsert 的功能并具有通用添加新字段的特点。

results.forEach(function (item) {
var prx = item['price'];  // capture price....

    // ...and now REMOVE it.  This is because fields cannot appear in                               
    // both $set and $setOnInsert.  Our trick here is to make the $setOnInsert                         
    // generic.  ANY fields that are NOT itemNumber or price will automatically                     
    // be added upon first insert.  It should be obvious that if you need                           
    // to upsert more things (i.e. more things to $set), then delete them from                      
    // the object too.  Note: $setOnInsert will only store the fields from                          
    // item upon first insert.  New fields in later items with an existing                          
    // key will NOT be updated.  Comment out the delete and see the error
    // message re. path conflict:                                                                    
delete item['price'];

rc = csvModel.findOneAndUpdate(
{ itemNumber: item["itemNumber"] },
{
$set: { price: prx },
$setOnInsert: item // Ah! Set the WHOLE OBJECT.
},
{ upsert: true }
);
rc.then(data => data)
});