保存Mongoose文档时出现版本错误 [英] Version error on saving Mongoose docs

问题描述

我有一个问题 - 不确定我做错了什么或者是一个错误。我有一些产品 - 每个产品都有一系列的变化。我想浏览一些数据并将其加载到这些变体中，但我遇到了一些VersionError：找不到匹配的文档错误。

I have an issue - not sure if I am doing something wrong or it's a bug. I have some products - each of these has an array of variations. I want to go through some data and load it in these variations but I experience a number of 'VersionError: No matching document found' errors.

以为我正在参加比赛条件（我按顺序为我修改的每个变体保存相同的文档）我使用asyc.eachSeries（）但没有帮助。一次加载导致文档错误的错误不会产生错误，因此它似乎与某些竞争条件有关但我无法追踪它。

Thinking I was having a race condition (I am sequenctially saving the same document for each of its variations that I modify) I used asyc.eachSeries() but that did not help. Loading the error causing documents one at the time does not yield the error so it seems related to some race condition but I cannot track it down.

架构：

var Product = new Schema({
  title: {
    type: String,
  },  
  variations: {
    type: Array
  }
});

示例代码：

// Some data to load - the 'variant' is the index of the variations array above
var records = [{
  code: 'foo',
  id: '50ba9c647abe1789f7000073',
  variant: 0
}, {
  code: 'bar',
  id: '50ba9c647abe1789f7000073',
  variant: 1
}, {
  code: 'foobar',
  id: '50ba9c647abe1789f7000073',
  variant: 2
}];

var iterator = function(item, cb) {
  Product.findById(item.id).exec(function(err, product) {
    if(err) {
      return cb(err);
    }
    if (product) {
      product.variations[item.variant].code = item.code.trim();
      product.markModified('variations');
      product.save(function(err, p) {
        return cb(err);
      });
    } else {
      return cb('Missing product');
    }
  });
};

async.eachSeries(records, iterator, function(err) {
  process.exit(1);
});

推荐答案

我认为问题在于你如何定义你的架构。让变体成为自己的模式并让产品模式使用它作为子doc更好。我会改变它看起来像这样：

I think the problem is how you've defined your schema. It's much to better to have variant be it's own schema and have the product schema use that as a sub doc instead. I would change it to look something like this:

var Variant = new Schema({
    code: String,
})

var Product = new Schema({
    title: String,
    variants: [Variant]
})

然后你可以像这样记录：

Then you could go through the records like so:

var variants = product.variants
for (i in variants) {
    var variant = variants[i]
    variant.code = records[i].code
    variant.save(function(err) {
        ...
    })
}

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