[英]How to retreive an object from an array of Objects in mongodb given a objectid
我有一系列评论,我只想从模式内的一组对象中检索评论。
这是我的架构:
const sellerSchema = new mongoose.Schema({
user: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
unique: true,
},
reviews: [
{
by: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
unique: true,
},
title: {
type: String,
},
message: {
type: String,
},
rating: Number,
imagesUri: [{ String }],
timestamp: {
type: Date,
default: Date.now,
},
},
],
});
如果 'by' 将是 req.user._id,我如何从数组中获得单个评论。 我有以前的代码,但它不能只检索满足查询的评论。
try {
const seller_id = mongoose.Types.ObjectId(req.params._id);
const review = await Seller.findOne(
{ _id: seller_id },
{ reviews: { $elemMatch: { by: req.user._id } } } //get the review that matches to the user_id
);
res.status(200).send(review);
} catch (err) {
//sends the status code with error code message to the user
res.status(502).send({
error: "Error retreiving review.",
});
}
这将检索整个卖方文档,但我只想使用给定的 user_id === by: ObjectID 检索对象评论
试试看
try {
const seller_id = mongoose.Types.ObjectId(req.params._id);
const review = await Seller.findOne(
{ _id: seller_id , "reviews.by": req.user._id}, { "reviews.$": 1 }
);
res.status(200).send(review);
}
尝试将用户_id
也转换为ObjectId
并将您的条件统一到一个对象中:
try {
const seller_id = mongoose.Types.ObjectId(req.params._id);
const user_id = mongoose.Types.ObjectId(req.user._id);
const review = await Seller.findOne({
_id: seller_id,
reviews: { $elemMatch: { by: user_id } },
});
res.status(200).send(review);
} catch (err) {
//sends the status code with error code message to the user
res.status(502).send({
error: 'Error retreiving review.',
});
}
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