Embedded Documents
Embedded documents are documents with schemas of their own that are part of other documents (as items within an array).
Embedded documents enjoy all the same features as your models. Defaults, validators, middleware. Whenever an error occurs, it's bubbled to the save()
error callback, so error handling is a snap!
Mongoose interacts with your embedded documents in arrays atomically, out of the box.
Definition and initialization
When you define a Schema like this:
var Comments = new Schema({
title : String
, body : String
, date : Date
});
var BlogPost = new Schema({
author : ObjectId
, title : String
, body : String
, date : Date
, comments : [Comments]
, meta : {
votes : Number
, favs : Number
}
});
mongoose.model('BlogPost', BlogPost);
The comments
key of your BlogPost
documents will then be an instance of DocumentArray
. This is a special subclassed Array
that can deal with casting, and has special methods to work with embedded documents.
Adding an embedded document to an array
// retrieve my model
var BlogPost = mongoose.model('BlogPost');
// create a blog post
var post = new BlogPost();
// create a comment
post.comments.push({ title: 'My comment' });
post.save(function (err) {
if (!err) console.log('Success!');
});
Removing an embedded document
BlogPost.findById(myId, function (err, post) {
if (!err) {
post.comments[0].remove();
post.save(function (err) {
// do something
});
}
});
Finding an embedded document by id
DocumentArray
s have an special method id
that filters your embedded documents by their _id
property (each embedded document gets one):
Consider the following snippet:
post.comments.id(my_id).remove();
post.save(function (err) {
// embedded comment with id `my_id` removed!
});