我已经检查了StackOverflow
上的其他条目,但没有帮助。
我建立一个RESTapi
与node.js
,以及我使用MongoDB
与mongoose
我有一个Schema
,其中包含三种不同的模型。我能够将POST
请求保存到条目。我确定该条目已保存,因为我选中了atlas.mongo
。但是,当我尝试使用GET
请求时遇到问题。
出现此错误:
Cast即可的ObjectId失败值 “” 在路径 “_id” 为模型
这些是我的模型 :(这些模型位于不同的文件中)
const Model1 = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
word1: { type: [String], require: true }
});
----------------------------------------------
const Model2 = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
word2: { type: [String], require: true }
});
----------------------------------------------
const Model3 = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
element1: { type: [String], default: ""},
element2: { type: [String], default: ""}
});
----------------------------------------------
const Word = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
md3: { type: mongoose.Schema.Types.Mixed, ref: 'Model3', require: true },
md2: { type: mongoose.Schema.Types.Mixed, ref: 'Model2', require: true },
md1: { type: mongoose.Schema.Types.Mixed, ref: 'Model1', require: true }
});
这是我的 POST 请求:
exports.entry_create = (req, res, next) => {
const newModel3 = new Model3({
_id: new mongoose.Types.ObjectId(),
element1: req.body.element1,
element2: req.body.element2
});
const newModel2 = new Model2({
_id: new mongoose.Types.ObjectId(),
word2: req.body.word2
});
const newModel1 = new Model1({
_id: new mongoose.Types.ObjectId(),
word1: req.body.word1
});
const newEntry = new Word({
_id: new mongoose.Types.ObjectId(),
md3: newModel3,
md2: newModel2,
md1: newModel1
});
newEntry
.save(); // i have also then() and catch() part
};
这是我在Postman
上遇到错误的地方
exports.entry_get_all = (req, res, next) => {
Word.find()
.select('_id md3 md2 md1')
.populate('md3')
.populate('md2')
.populate('md1')
.exec()
.then(docs => {
res.status(200).json({
numOfEntries: docs.length,
Entries: docs.map(doc => {
return {
_id: doc._id,
md3: doc.md3,
md2: doc.md2,
md1: doc.md1,
request: { type: 'GET' }
}
})
});
}); // i have also catch() part
};
可能是什么问题?为_id
的{{1}}返回md3, md2 & md1
?
答案 0 :(得分:1)
我认为这与您引用的md1,md2和md3有关。引用另一个模型的方式是通过_id(在您的情况下为_id)和ObjectId。话虽如此,当您定义md1,md2和md3时,您说的是混合类型,而不是ObjectId。改为这样做:
const Word = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
md3: { type: mongoose.Schema.Types.ObjectId, ref: 'Model3', require: true },
md2: { type: mongoose.Schema.Types.ObjectId, ref: 'Model2', require: true },
md1: { type: mongoose.Schema.Types.ObjectId, ref: 'Model1', require: true }
});
还请注意:创建模型实例时,无需显式创建新的ObjectId。如果使用猫鼬,它将为您创建_id!因此,您可以像这样创建新的Word
:
let md1 = null;
let md2 = null;
let md3 = null;
const newModel3 = new Model3({
element1: req.body.element1,
element2: req.body.element2
});
// Save newModel3
newModel3.save()
.then((_md3) => {
md3 = _md3;
const newModel2 = new Model2({
word2: req.body.word2
});
return newModel2.save();
})
.then((_md2) => {
md2 = _md2;
const newModel1 = new Model1({
word1: req.body.word1
});
return newModel1.save();
})
.then((_md1) => {
md1 = _md1
const newEntry = new Word({
md3: md3._id,
md2: md2._id,
md1: md1._id
});
return newEntry.save();
})