嵌入式文档的猫鼬更新

Question

我正在慢慢发疯，试图了解如何在 mongoose 中更新嵌入文档的值，并编写了一些演示该问题的 node.js 代码。

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

mongoose.connect('mongodb://localhost/mongoose_broken');

var ASchema = new Schema({
   value : { type: String, index: { unique: true } },
   bs    : [BSchema],
});
var BSchema = new Schema({
   value : { type: String },
});
var A = mongoose.model('A', ASchema);
var B = mongoose.model('B', BSchema);

// Add an entry of A, with 1 embedded B
//
var a = new A();
a.value = "hello";
var b = new B();
b.value = "world";
a.bs.push(b);

a.save(function(err) {
   if (err) {
      console.log("Error occured during first save() " + err);
      return;
   }

   // Now update a by changing a value inside the embedded b
   //
   A.findOne({ value: 'hello' }, function(err, doc) {
      if (err) { console.log("Error occured during find() " + err); return; }

      doc.bs[0].value = "moon";

      doc.save(function(err) {
         if (err) console.log("Error occuring during second save()");

         // Check b was updated?
         //
         if (doc.bs[0].value != "moon") {
            console.log ("b was not updated! (first check)");   
         } else {
            console.log ("b looks like it was updated (first check)");

            // Do a fresh find
            //
            A.findOne({value: "hello"}, function(err, doc_2) {
               if (err) { console.log("Error occured during second find() " + err); return; }

               if (doc_2.bs[0].value != "moon") {
                  console.log ("b was not updated! (second check)");   
               } else {
                  console.log ("b looks like it was updated (second check)");
               }
            });
         }
      });
   });
});

运行的输出是：

b looks like it was updated (first check)
b was not updated! (second check)

知道为什么嵌入文档的更新没有保存吗？

Answer 1

您必须先声明子架构，然后才能在父架构中使用它们。

var BSchema = new Schema({
  value : { type: String },
});    
var ASchema = new Schema({
  value : { type: String, index: { unique: true } },
  bs    : [BSchema],
});