早上好
所以我似乎在用Node.js和Mongoose填充字段时遇到问题。它只是出现一个空白数组:
结果:(JSON)
[
{
"courseassignments": [],
"_id": "5db56ceb4cc2c92824ae2651",
"name": "Garibaldi",
"website": "www.garibaldi.org.uk",
"__v": 0
},
{
"courseassignments": [],
"_id": "5db56d074cc2c92824ae2652",
"name": "Kirk Hallam",
"website": "www.kirkhallamacademy.co.uk",
"__v": 0
}
]
以下是我正在使用的调用populate函数的代码,以及我用于每个数据的模型。这很奇怪。
* school.js(模型)*
// Require modules within our file:
const mongoose = require('mongoose')
const schoolSchema = new mongoose.Schema({
name: {
type: String,
required: true,
unique: true,
trim: true
},
website: {
type: String,
required: true,
trim: true
},
logo: {
type: Buffer
},
courseassignments: [{
type: mongoose.Schema.Types.ObjectID,
ref: 'CourseAssignment'
}]
})
// Export the user to use within other files:
const school = mongoose.model('School', schoolSchema)
module.exports = school
courseassignment.js(模型)
// Require modules within our file:
const mongoose = require('mongoose')
const courseAssignmentSchema = new mongoose.Schema({
school: {
type: mongoose.Schema.Types.ObjectID,
required: true,
ref: 'School'
},
course: {
type: mongoose.Schema.Types.ObjectID,
required: true,
ref: 'Course'
}
})
// Export the user to use within other files:
const courseAssignment = mongoose.model('CourseAssignment', courseAssignmentSchema)
module.exports = courseAssignment
*提取数据的代码:(在app.js中)*
router.get('/school', async (req, res) => {
const schools = await School.find({}).populate({ path: 'courseassignments' })
res.send(schools)
})
答案 0 :(得分:1)
我将从School模型中删除课程参考,并利用虚拟填充。
因此,请按以下步骤操作:
const mongoose = require('mongoose')
const schoolSchema = new mongoose.Schema({
name: {
type: String,
required: true,
unique: true,
trim: true
},
website: {
type: String,
required: true,
trim: true
},
logo: {
type: Buffer
}
}, {
toJSON: { virtuals: true },
toObject: { virtuals: true }
})
schoolSchema.virtual("courseassignments", {
ref: "CourseAssignment",
foreignField: "school",
localField: "_id"
})
const school = mongoose.model('School', schoolSchema)
module.exports = school
这时,当您达到学校终点时,您的响应将是这样。 (我只显示一个简短的项目。)
[
{
"_id": "5db5a809cfc9951770d5078a",
"name": "school 1",
"website": "school 1 website",
"__v": 0,
"courseassignments": [
{
"_id": "5db5a892cfc9951770d50790",
"school": "5db5a809cfc9951770d5078a",
"course": "5db5a847cfc9951770d5078d",
"__v": 0
},
{
"_id": "5db5a89ccfc9951770d50791",
"school": "5db5a809cfc9951770d5078a",
"course": "5db5a851cfc9951770d5078e",
"__v": 0
},
{
"_id": "5db5a8a1cfc9951770d50792",
"school": "5db5a809cfc9951770d5078a",
"course": "5db5a858cfc9951770d5078f",
"__v": 0
}
],
"id": "5db5a809cfc9951770d5078a"
},
...
...
]
如果您还想访问“课程名称”(我认为这很好),
const mongoose = require('mongoose')
const courseAssignmentSchema = new mongoose.Schema({
school: {
type: mongoose.Schema.Types.ObjectID,
required: true,
ref: 'School'
},
course: {
type: mongoose.Schema.Types.ObjectID,
required: true,
ref: 'Course'
}
}, {
toJSON: { virtuals: true },
toObject: { virtuals: true }
})
courseAssignmentSchema.pre(/^find/, function (next) {
this.populate({
path: 'course'
});
next();
});
// an index may be required like this
//courseAssignmentSchema.index({ school: 1, course: 1 }, { unique: true });
const courseAssignment = mongoose.model('CourseAssignment', courseAssignmentSchema)
module.exports = courseAssignment
并且与此相关的结果将包含与课程相关的字段,例如课程名称。
[[
{
"_id": "5db5a809cfc9951770d5078a",
"name": "school 1",
"website": "school 1 website",
"__v": 0,
"courseassignments": [
{
"_id": "5db5a892cfc9951770d50790",
"school": "5db5a809cfc9951770d5078a",
"course": {
"_id": "5db5a847cfc9951770d5078d",
"name": "course 1",
"__v": 0
},
"__v": 0,
"id": "5db5a892cfc9951770d50790"
},
{
"_id": "5db5a89ccfc9951770d50791",
"school": "5db5a809cfc9951770d5078a",
"course": {
"_id": "5db5a851cfc9951770d5078e",
"name": "course 2",
"__v": 0
},
"__v": 0,
"id": "5db5a89ccfc9951770d50791"
},
{
"_id": "5db5a8a1cfc9951770d50792",
"school": "5db5a809cfc9951770d5078a",
"course": {
"_id": "5db5a858cfc9951770d5078f",
"name": "course 3",
"__v": 0
},
"__v": 0,
"id": "5db5a8a1cfc9951770d50792"
}
],
"id": "5db5a809cfc9951770d5078a"
},
...
...
]
文档: