猫鼬为什么要添加空白数组? [英] Why does Mongoose add blank arrays?

问题描述

我正尝试通过我的node.js应用程序将Mongoose用作MongoDB的ODM.我注意到，当我设计带有嵌入式文档的架构时，如果不向其添加值，它将在Mongo中存储一个空白数组"[]".为什么是这样?我正在尝试将历史更改存储到记录中，而空白数组将意味着该更改删除了该值.这是示例架构.

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}},
})

当我保存仅包含名称和子域的文档时，这就是生成的文档.

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

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

为什么默认情况下会添加带有空白数组的产品，我该如何停止呢?

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

推荐答案

您可以通过定义以下架构来解决:

You can workaround by define the schema like below:

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

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