node.js 使用不是 id 的字段填充猫鼬模型
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Populate a mongoose model with a field that isn't an id
提问by angulord
Is it possible to populate a mongoose model with a field of a reference model that isn't the _id ... e.g. a username.
是否可以使用不是 _id 的参考模型字段填充猫鼬模型......例如用户名。
so something like
所以像
var personSchema = Schema({
_id : Number,
name : String,
age : Number,
stories : { type: String, field: "username", ref: 'Story' }
});
采纳答案by leesei
You may use the populate()API.
The API is more flexible, you don't have to specify refand fieldin the Schema.
您可以使用populate()API。API 更加灵活，您不必在 Schema 中指定ref和field。
http://mongoosejs.com/docs/api.html#document_Document-populatehttp://mongoosejs.com/docs/api.html#model_Model.populate
http://mongoosejs.com/docs/api.html#document_Document-populate http://mongoosejs.com/docs/api.html#model_Model.populate
You can mix and match with find().
您可以与find().
回答by Frosty Z
This is supported since Mongoose 4.5, and is called virtuals population.
自Mongoose 4.5起支持此功能，称为虚拟人口。
You have to define your foreign keys relationshipsafter your schemas definitionsand before creating models, like this:
您必须在架构定义之后和创建模型之前定义外键关系，如下所示：
// Schema definitions
BookSchema = new mongoose.Schema({
...,
title: String,
authorId: Number,
...
},
// schema options: Don't forget this option
// if you declare foreign keys for this schema afterwards.
{
toObject: {virtuals:true},
// use if your results might be retrieved as JSON
// see http://stackoverflow.com/q/13133911/488666
//toJSON: {virtuals:true}
});
PersonSchema = new mongoose.Schema({id: Number, ...});
// Foreign keys definitions
BookSchema.virtual('author', {
ref: 'Person',
localField: 'authorId',
foreignField: 'id',
justOne: true // for many-to-1 relationships
});
// Models creation
var Book = mongoose.model('Book', BookSchema);
var Person = mongoose.model('Person', PersonSchema);
// Querying
Book.find({...})
// if you use select() be sure to include the foreign key field !
.select({.... authorId ....})
// use the 'virtual population' name
.populate('author')
.exec(function(err, books) {...})
回答by Leo Gao
It seems they enforce to use _id, and maybe we can customize it in the future.
似乎他们强制使用_id，也许我们将来可以自定义它。
Here is the issue on Github https://github.com/LearnBoost/mongoose/issues/2562
这是 Github 上的问题https://github.com/LearnBoost/mongoose/issues/2562
回答by Lotus
This is an example of using the $lookup aggregate to populate a model called Invite with the respective User based on the corresponding emailfield:
这是使用 $lookup 聚合根据相应email字段使用相应用户填充名为 Invite 的模型的示例：
Invite.aggregate(
{ $match: {interview: req.params.interview}},
{ $lookup: {from: 'users', localField: 'email', foreignField: 'email', as: 'user'} }
).exec( function (err, invites) {
if (err) {
next(err);
}
res.json(invites);
}
);
It's probably quite similar to what you're trying to do.
它可能与您尝试做的非常相似。
