mongoose連表查詢2

1.解讀mongoose的populate

    1.Query#populate

var mongoose = require('mongoose') , Schema = mongoose.Schema var personSchema = Schema({ _id : Number, // 只支持ObjectId,Number,String,Buffer，就這幾個引用類型，ref匹配的只有這個_id

 name : String, 

 age : Number, 

 stories : [{ type: Schema.Types.ObjectId, ref: 'Story' }] }); 

var storySchema = Schema({ 
 _creator : { type: Number, ref: 'Person' }, 
　　title : String, fans : [{ type: Number, ref: 'Person' }] 
});

var Story = mongoose.model('Story', storySchema); 
var Person = mongoose.model('Person', personSchema);

_id的類型是:ObjectId, Number, String, and Buffer are valid for use as refs.
那麼_id的類型是:ObjectIdNumberStringBuffer_crestor 存儲的類型必須與這個_id的數據類型一直,只能關聯_id.

在文檔關聯使用ref必定要注意，關聯的那個model只能匹配_id這個字段，你要是搞個自動生成的啥的一律無效