mongodb 在猫鼬中引用另一个模式
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Referencing another schema in Mongoose
提问by Gorkem Yurtseven
if I have two schemas like:
如果我有两个模式，如：
var userSchema = new Schema({
twittername: String,
twitterID: Number,
displayName: String,
profilePic: String,
});
var User = mongoose.model('User')
var postSchema = new Schema({
name: String,
postedBy: User, //User Model Type
dateCreated: Date,
comments: [{body:"string", by: mongoose.Schema.Types.ObjectId}],
});
I tried to connect them together like the example above but I couldn't figure out how to do it. Eventually, if I can do something like this it would make my life very easy
我试图像上面的例子一样将它们连接在一起，但我不知道该怎么做。最终，如果我能做这样的事情，我的生活就会变得很轻松
var profilePic = Post.postedBy.profilePic
回答by nicksweet
It sounds like the populate method is what your looking for. First make small change to your post schema:
听起来 populate 方法正是您要找的。首先对您的帖子架构进行小的更改：
var postSchema = new Schema({
name: String,
postedBy: {type: mongoose.Schema.Types.ObjectId, ref: 'User'},
dateCreated: Date,
comments: [{body:"string", by: mongoose.Schema.Types.ObjectId}],
});
Then make your model:
然后制作你的模型：
var Post = mongoose.model('Post', postSchema);
Then, when you make your query, you can populate references like this:
然后，当您进行查询时，您可以像这样填充引用：
Post.findOne({_id: 123})
.populate('postedBy')
.exec(function(err, post) {
// do stuff with post
});
回答by fino
Addendum: No one mentioned "Populate" --- it is very much worth your time and money looking at Mongooses Populate Method : Also explains cross documents referencing
附录：没有人提到“填充”——看猫鼬填充方法非常值得你花时间和金钱：还解释了交叉文档引用
回答by D. Lowe
Late reply, but adding that Mongoose also has the concept of Subdocuments
回复晚了，但补充说Mongoose也有子文档的概念
With this syntax, you should be able to reference your userSchemaas a type in your postSchemalike so:
使用此语法，您应该能够像这样引用您userSchema的类型postSchema：
var userSchema = new Schema({
twittername: String,
twitterID: Number,
displayName: String,
profilePic: String,
});
var postSchema = new Schema({
name: String,
postedBy: userSchema,
dateCreated: Date,
comments: [{body:"string", by: mongoose.Schema.Types.ObjectId}],
});
Note the updated postedByfield with type userSchema.
请注意postedBy带有 type的更新字段userSchema。
This will embed the user object within the post, saving an extra lookup required by using a reference. Sometimes this could be preferable, other times the ref/populate route might be the way to go. Depends on what your application is doing.
这会将用户对象嵌入帖子中，从而节省使用引用所需的额外查找。有时这可能更可取，其他时候 ref/populate 路线可能是要走的路。取决于您的应用程序在做什么。
