架构定义
js
var TeamSchema = new Schema({
// Team Name.
name: String,
lead: String,
students :type: [{
block : Number,
status : String,
student : {
type: Schema.ObjectId,
ref: 'Student'
}]
});
js
var StudentSchema = new Schema({
name: String,
rollNo : Number,
class : Number
});
如何填充“学生”以获得输出，如下所示：
团队
{
"__v": 1,
"_id": "5252875356f64d6d28000001",
"students": [
{
"__v": 1,
"_id": "5252875a56f64d6d28000002",
block : 1,
status : joined,
"student": {
"name": Sumeeth
"rollNo" : 2
"class" : 5
}
},
{
"__v": 1,
"_id": "5252875a56f64d6d28000003",
block : 1,
status : joined,
"student": {
"name": Sabari
"rollNo" : 3
"class" : 4
}
}
],
"lead": "Ratha",
}
这是我使用Mongoose获取文档的JS：
Team.findOne({
_id: req.team._id
})
.populate('students')
.select('students')
.exec(function(err, team) {
console.log(team);
var options = {
path: 'students.student',
model: 'Student'
};
Student.populate(team.students,options,function(err, students) {
console.log(students);
if (err) {
console.log(students);
res.send(500, {
message: 'Unable to query the team!'
});
} else {
res.send(200, students);
}
});
});
在我的控制台输出中，我得到以下内容：
{ _id: 53aa434858f760900b3f2246,
students
[ { block : 1
status: 'joined'
_id: 53aa436b58f760900b3f2249 },
{ block : 1
status: 'joined'
_id: 53aa436b58f760900b3f2250 }]
}
预期输出是：
{ _id: 53aa434858f760900b3f2246,
students
[ { block : 1
status: 'joined'
student :{
"name": Sumeeth
"rollNo" : 2
"class" : 5
}
},
{ block : 1
status: 'joined'
student :{
"name": Sabari
"rollNo" : 3
"class" : 4
}
}
]
}
有人请帮帮我，我错了。我应该如何使用。填充，这样，我就可以得到整个学生对象，而不仅仅是它的id。
参考：在猫鼬中填充嵌套数组
我一直面临着同样的问题。我使用此代码进行救援：
Team.findOne({_id: req.team._id})
.populate({ path: "students.student"})
.exec(function(err, team) {
console.log(team);
});
这是你想要的简化版本。
基本数据要设置，首先是“学生”：
{
"_id" : ObjectId("53aa90c83ad07196636e175f"),
"name" : "Bill",
"rollNo" : 1,
"class" : 12
},
{
"_id" : ObjectId("53aa90e93ad07196636e1761"),
"name" : "Ted",
"rollNo" : 2,
"class" : 12
}
然后是“团队”集合：
{
"_id" : ObjectId("53aa91b63ad07196636e1762"),
"name" : "team1",
"lead" : "me",
"students" : [
{
"block" : 1,
"status" : "Y",
"student" : ObjectId("53aa90c83ad07196636e175f")
},
{
"block" : 2,
"status" : "N",
"student" : ObjectId("53aa90e93ad07196636e1761")
}
]
}
你是这样做的：
var async = require('async'),
mongoose = require('mongoose');
Schema = mongoose.Schema;
mongoose.connect('mongodb://localhost/team');
var teamSchema = new Schema({
name: String,
lead: String,
students: [{
block: Number,
status: String,
student: {
type: Schema.ObjectId, ref: 'Student'
}
}]
});
var studentSchema = new Schema({
name: String,
rollNo: Number,
class: Number
});
var Team = mongoose.model( "Team", teamSchema );
var Student = mongoose.model( "Student", studentSchema );
Team.findById("53aa91b63ad07196636e1762")
.select('students')
.exec(function(err, team) {
console.log( team );
async.forEach(team.students, function(student,callback) {
Student.populate(
student,
{ "path": "student" },
function(err,output) {
if (err) throw err;
callback();
}
);
},function(err) {
console.log( JSON.stringify( team, undefined, 4 ) );
});
});
它会给你结果：
{
"_id": "53aa91b63ad07196636e1762",
"students": [
{
"block": 1,
"status": "Y",
"student": {
"_id": "53aa90c83ad07196636e175f",
"name": "Bill",
"rollNo": 1,
"class": 12
}
},
{
"block": 2,
"status": "N",
"student": {
"_id": "53aa90e93ad07196636e1761",
"name": "Ted",
"rollNo": 2,
"class": 12
}
}
]
}
你真的不需要“异步”模块，但我只是“习惯”了。它不“阻塞”，所以我认为它更好。
所以你可以看到，你最初的。填充（）调用没有做任何事情，因为它期望从一个数组输入的外部集合中的_id值中“键”掉，严格来说，这个“键”不是在包含“外键”的“学生”上。
我确实在最近的回答中提到了这一点，也许并不完全针对你的情况。似乎你的搜索没有找到正确的“相同的答案”（尽管不完全）供你参考。
你想太多了。让猫鼬为你做这项工作。
Team.findOne({
_id: req.team._id
})
.populate({path:'students'})
.exec(function(err, team) {
console.log(team);
});
这将以文件的形式返回学生，而不仅仅是id。
