Question

我有两个模型：Document和URL：

const DocumentSchema = new Schema({
  text: String,
  path: String,
  urls: [{ type: Schema.Types.ObjectId, ref: 'URL' }],
});

const URLSchema = new Schema({
  url: String,
  display_url: String,
  ref: Boolean,
});

我想从数组中创建多个文档，所以我要做的是：

const documents = [{ ..., urls: [ ... ] }, ...];

Document.create(documents, (err, docs) => {
    ...
});

然后我收到错误urls: Cast to Array failed for value。我想这是因为我想添加网址，但我还没有将它们添加到数据库中（所以我没有ID）。

有没有办法创建一个Schema，所以我可以添加它们而不先创建URL？（所以它们会自动添加？）

Answer 1

您可以使用cascade文档中间件在save上实施Document。您可以在URL保存的输出中看到const Schema = mongoose.Schema; const DocumentSchema = new Schema({ text: String, path: String, urls: [{ type: Schema.Types.ObjectId, ref: 'URL' }], }); const URLSchema = new Schema({ url: String, display_url: String, ref: Boolean, }); const URL = mongoose.model('URL', URLSchema, 'urls'); DocumentSchema.pre('save', function(next){ URL.insertMany(this.urls, function(err, res){ if(err) throw err; next(); }) }); const Document = mongoose.model('Document', DocumentSchema, 'documents'); var u1 = new URL({url : 'www.google.com'}); var d = new Document({text: 'test text', urls : [u1]}) d.save(function(err, doc){ console.log(doc) })也保存到集合

mongoose middleware documentation

saravana@ubuntu:~/node-mongoose$ node so2.js
`open()` is deprecated in mongoose >= 4.11.0, use `openUri()` instead, or set the `useMongoClient` option if using `connect()` or `createConnection()`. See http://mongoosejs.com/docs/connections.html#use-mongo-client
Mongoose: urls.insertMany([ { __v: 0, _id: 5a5b345f98f048281d88eac1, url: 'www.google.com' } ], {})
Mongoose: documents.insert({ text: 'test text', _id: ObjectId("5a5b345f98f048281d88eac2"), urls: [ ObjectId("5a5b345f98f048281d88eac1") ], __v: 0 })
{ __v: 0,
  text: 'test text',
  _id: 5a5b345f98f048281d88eac2,
  urls: [ { url: 'www.google.com', _id: 5a5b345f98f048281d88eac1 } ] }
^C
saravana@ubuntu:~/node-mongoose$

输出

{{1}}

Mongoose创建 - 创建包含其他对象的对象

1 个答案: