如何在mongoose中更新嵌入文档中的嵌入文档？

Question

我在node.js中构建一个使用mongodb和mongoose的API.目前我在嵌入式文档(Schema中的Schema)中有一个嵌入式文档,它根本没有持久存储到数据库中,我已尽力而为但没有运气.

我在mongoose中定义了Schema:

var BlogPostSchema = new Schema({
  creationTime: { type: Date, default: Date.now },
  author: { type: ObjectId, ref: "User" },
  title: { type: String },
  body: { type: String },
  comments: [CommentSchema]
});

var CommentSchema = new Schema({
  creationTime: { type: Date, default: Date.now },
  user: { type: ObjectId, ref: "User" },
  body: { type: String, default: "" },
  subComments: [SubCommentSchema]
});

var SubCommentSchema = new Schema({
  creationTime: { type: Date, default: Date.now },
  user: { type: ObjectId, ref: "User" },
  body: { type: String, default: "" }
});

我执行的代码如下:

// Create a comment
app.post("/posts/:id/comments", function(req, res, next) {
  Posts.find({ _id : req.params.id }, function(err, item){
    if(err) return next("Error finding blog post.");                
    item[0].comments.push(new Comment(JSON.parse(req.body)));
    item[0].save(); // <= This actually saves and works fine
    respond(req, res, item[0].comments, next);
  });
});

// Create a subcomment
app.post("/posts/:id/comments/:commentid/subcomments", function(req, res, next) {
  Posts.find({ _id : req.params.id }, function(err, item){
    if(err) return next("Error finding blog post.");
    item[0].comments[req.params.commentid - 1].subcomments.push(new SubComment(JSON.parse(req.body)));
    item[0].save(); // <= This completes (without error btw) but does not persist to the database
    respond(req, res, item[0].comments[req.params.commentid - 1].subcomments, next);
  });
});

我可以毫无问题地创建包含评论的博客帖子,但出于某种原因,我无法在评论中创建子评论.Blog Post文档实际上在执行期间打印到控制台时附加了注释和子注释 - 只有它不保存到数据库(它保存带有注释的Blog Post,但没有子注释).

我试图在comments数组上"markModified",但没有改变:

Posts.markModified("comments"); // <= no error, but also no change
...
Posts.comments.markModified("subcomments"); // <= produces an error: "TypeError: Object [object Object] has no method 'markModified'"

Answer 1

问题解决了.我得到了Aaron Heckmann对猫鼬谷歌集团的回答:

在将子模式传递给父模式之前,请始终声明它们,否则传递未定义.

SubCommentSchema应该是第一个,然后是Comment,然后是BlogPost.

在颠倒模式之后它起作用了.