为什么猫鼬添加空白数组? [英] Why does Mongoose add blank arrays?

问题描述

我正在尝试使用 Mongoose 作为 MongoDB 的 ODM 和我的 node.js 应用程序.我注意到，当我设计一个带有嵌入式文档的模式时，如果我不向它添加值，它会在 Mongo 中存储一个空白数组[]".为什么是这样?我正在尝试存储对记录的历史更改，而空白数组将意味着该更改删除了该值.这是一个示例架构.

I am trying to start using Mongoose as an ODM for MongoDB with my node.js application. I have noticed that when I design a schema with an embedded document that if I don't add a value to it, it store a blank array "[]" in Mongo. Why is this? I am trying to store historical changes to records and a blank array would mean that that change deleted the value. Here is a sample schema.

schema.Client = new mongoose.Schema({
    name:{type:String, required:true},
    products:[{
        name:{type:String, index:true},
        startDate:Date,
        endDate:Date
    }],
    subdomain:{type:String, index:{unique:true}},
})

这是我保存只有名称和子域的文档时生成的文档.

Here is the resulting document when I save a document with just name and subdomain.

{
    "name": "Smith Company",
    "products": [],
    "subdomain": "smith"
}

为什么它默认添加带有空白数组的产品，我该如何阻止它?

Why did it add products with a blank array by default and how can I stop it?

推荐答案

您可以通过定义如下架构来解决:

You can workaround by define the schema like below:

products: {
  type: [{
    name:String,
    startDate:Date,
    endDate:Date
  }],
  default: undefined
}

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