猫鼬与自定义字段的关系

问题描述：

我已经看到了很多有关猫鼬和关系的例子，但是如何在自定义字段中创建对另一个实体的引用?

I've seen many examples about mongoose and relations, but how can I create a reference to another entity into a custom field ?

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');
mongoose.connection.once('open', function(){

  var Author = m.model('Author', new m.Schema({
    name: String,
    slugname: String
  }));
  var Book = m.model('Book', new m.Schema({
    title: String,
    author: {type: String, ref: 'Author.slugname'}
  }));

});

在上面的代码中，我将Book.author链接到Author.slugname中.只是我不知道这是否是正确的方法.

In the code above, I'm linking Book.author into Author.slugname. it is just that I don't if this is the right way to do it.

答

不，您不能.猫鼬总是使用_id字段链接文档.但是...

No, you can't. Mongoose always use _id field to link documents. But...

您可以使用所需的任何数据类型为每个文档设置自己的_id.只有两个限制:

You can set your own _id for each document, using any datatype you want. There are only two restrictions:

它应该是唯一的
在文档的生命周期内不得更改

因此，不要添加新的slugname字段，而使用作者的_id作为别名:

So, instead of adding new slugname field, use author's _id as a slugname:

var Author = m.model('Author', new m.Schema({
  _id: String, // <-- slugname
  name: String
}));
var Book = m.model('Book', new m.Schema({
  title: String,
  author: { type: String, ref: 'Author' }
}));

猫鼬与自定义字段的关系

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