I'm new to NodeJS and MongoDB.
I wanna get user's profile with one user's following list. If I use RDB, it was so simple with EQ join but I didn't have much experience of MongoDB, I don't know how.
Sample data below.
// list of users
[
{
_id: "oid_1",
nickname: "user_01",
link: "url/user_01"
},
{
_id: "oid_2",
nickname: "user_02",
link: "url/user_02"
},
{
_id: "oid_3",
nickname: "user_03",
link: "url/user_03"
}
...
]
user_01's followList
[
{
followOid: "foid_1",
userOid: "user_01"
},
{
followOid: "foid_2",
userOid: "user_02"
},
]
My solution is, get follow list, then use loop with follows.findOne() like below
const dataSet = [];
Follow.getFollowerList(userId) // for pipeline, use promise
.exec()
.then( async (result) => { // no async-await, no data output...
for (let data of result) {
let temp = await Users.getUserInfo( // send query for each data, I think it's not effective
data.userId,
{ nickname: 1, link: 1 }
);
dataSet.push(temp);
}
return dataSet;
})
.then((data) => {
res.status(200).json(data);
})
.catch( ... )
I think it's not best solution. If you are good at mongodb, plz save my life :)
thanks
One option would be to use aggregation.
const userId = 'Fill with UserId';
const pipe = [
{
'$match': {
'_id': userId
}
}, {
'$lookup': {
'from': 'followListCollectionName',
'localField': '_id',
'foreignField': 'userOid',
'as': 'followList'
}
}
];
const result = await UserModel.aggregate(pipeline);
and then you can find an array in result which contains one user with given Id ( and more if there are with same Id) and result[0].followList you can find follow objects as array
Second Option is to use virtuals
https://mongoosejs.com/docs/tutorials/virtuals.html
but for this schema of your collection needs some changes.
Good luck
Related
Summary:
I am trying to Combine the result of Mongodb aggregation with a third party API and I can't find anything relevant to it.
Explanation:
The below Express route finds all Games that comes after the provided Date and have not been cancelled. The next step is to get some data of that single game from the Third party API and attach it to the object and continue further in the pipeline
Issue:
It seems that you can't have a XHR request inside the $function (I didn't find anything in the official documentation so I'm not sure on that)
const today = moment();
today.year(2021);
today.month(5);
let response = await Game.aggregate([
{
$match: {
$expr: {
$and: [
{ $gte: ["$date", moment(today).startOf('day').toDate()] },
{ $eq: ["$canceled", false] },
]
}
}
},
{ $sort: { date: 1 } },
{
$addFields: {
boxScore: {
$function:
{
body: async function (season, week, home_team) {
const result = await axios.get(
`SINGLEGAMEURL/${season}/${week}/${home_team}`,
{
headers: {
'Subscription-Key': 'SOMEKEY',
},
}
);
return result.data;
},
args: ["$season", '$week', 'home_team'],
lang: "js"
}
}
}
}
]);
I would really appreciate any help/direction on this, Cheers!
I doubt that you can use asynchronous functions in $function, because they return a promise that resolves to result.data, rather than the data themselves. Instead, consider performing the asynchronous operation in your express middleware, after the MongoDB operation. Something like this:
app.use("/path", async function(req, res) {
const today = moment();
today.year(2021);
today.month(5);
let response = await Game.aggregate([
{$match: ...},
{$sort: {date: 1}}
]).toArray();
await Promise.all(response.map(row => axios.get(
`SINGLEGAMEURL/${row.season}/${row.week}/${row.home_team}`,
{headers: {'Subscription-Key': 'SOMEKEY'}}
).then(function(result) {
row.boxScore = result.data;
})));
res.json(response);
});
(Probably the Promise.all can be avoided, but I'm not experienced enough with async/await to know how.)
is that posible to reuse already exec mongodb/mongoose query in nodejs?
for example i create query like this to check if user exist or not:
const inviter = await User.findOne({ _id: req.userData._id }).exec()
// there's bunch of code bellow here before update the user data
basically if i want to update the data, then i have to write the same code again and add update function like this:
User.findOneAndUpdate({ _id: req.userData._id }, { $push: { invited: recipient.value } }, { useFindAndModify: false })
is that posible to continue the first query and add short query to update based on result of the first query, for example like this:
inviter.update({ $push: { invited: recipient.value }).exec()
i know this code is not work..
you can use this approach :
User.findOne({ _id: req.userData._id }).exec((err, result) => {
if(result)
{
result.invited = recipient.value;
result.save((err) => {
if (err) // do something
});
}
})
}
I am trying to update a document in mongo with mongoose using updateOne method:
const updateResult = await UserModel.updateOne({
_id: mongoose.Types.ObjectId(userId)
}, {
$set: {
a: 'B'
}
})
userId contains a string of the ID of the user.
I have tried using the following
1. { _id: userId }
2. { email: theEmailOfTheUser }
But still, the updateResult is
n:0, nModified:0, ok:0
So I think it's must be something with the method itself and not in my query.
Also, when I'm trying to find the user using the query below, it can find it:
const user = await UserModel.find({
_id: userId
});
//user is found
Actually mongoose takes care of the $set and you do not have to add it. just:
const updateResult = await UserModel.updateOne({
_id: userId
}, {
a: 'B'
})
but the better solution would to just use findByIdAndUpdate():
const updateResult = await UserModel.findByIdAndUpdate(userId, {
a: 'B'
})
Background: Im developing an app that shows analytics for inventory management.
It gets an office EXCEL file uploaded, and as the file uploads the app convert it to an array of JSONs. Then, it comapers each json object with the objects in the DB, change its quantity according to the XLS file, and add a timestamp to the stamps array which contain the changes in qunatity.
For example:
{"_id":"5c3f531baf4fe3182cf4f1f2",
"sku":123456,
"product_name":"Example",
"product_cost":10,
"product_price":60,
"product_quantity":100,
"Warehouse":4,
"stamps":[]
}
after the XLS upload, lets say we sold 10 units, it should look like that:
{"_id":"5c3f531baf4fe3182cf4f1f2",
"sku":123456,
"product_name":"Example",
"product_cost":10,
"product_price":60,
"product_quantity":90,
"Warehouse":4,
"stamps":[{"1548147562": -10}]
}
Right now i cant find the right commands for mongoDB to do it, Im developing in Node.js and Angular, Would love to read some ideas.
for (let i = 0; i < products.length; i++) {
ProductsDatabase.findOneAndUpdate(
{"_id": products[i]['id']},
//CHANGE QUANTITY AND ADD A STAMP
...
}
You would need two operations here. The first will be to get an array of documents from the db that match the ones in the JSON array. From the list you compare the 'product_quantity' keys and if there is a change, create a new array of objects with the product id and change in quantity.
The second operation will be an update which uses this new array with the change in quantity for each matching product.
Armed with this new array of updated product properties, it would be ideal to use a bulk update for this as looping through the list and sending
each update request to the server can be computationally costly.
Consider using the bulkWrite method which is on the model. This accepts an array of write operations and executes each of them of which a typical update operation
for your use case would have the following structure
{ updateOne :
{
"filter" : <document>,
"update" : <document>,
"upsert" : <boolean>,
"collation": <document>,
"arrayFilters": [ <filterdocument1>, ... ]
}
}
So your operations would follow this pattern:
(async () => {
let bulkOperations = []
const ids = products.map(({ id }) => id)
const matchedProducts = await ProductDatabase.find({
'_id': { '$in': ids }
}).lean().exec()
for(let product in products) {
const [matchedProduct, ...rest] = matchedProducts.filter(p => p._id === product.id)
const { _id, product_quantity } = matchedProduct
const changeInQuantity = product.product_quantity - product_quantity
if (changeInQuantity !== 0) {
const stamps = { [(new Date()).getTime()] : changeInQuantity }
bulkOperations.push({
'updateOne': {
'filter': { _id },
'update': {
'$inc': { 'product_quantity': changeInQuantity },
'$push': { stamps }
}
}
})
}
}
const bulkResult = await ProductDatabase.bulkWrite(bulkOperations)
console.log(bulkResult)
})()
You can use mongoose's findOneAndUpdate to update the existing value of a document.
"use strict";
const ids = products.map(x => x._id);
let operations = products.map(xlProductData => {
return ProductsDatabase.find({
_id: {
$in: ids
}
}).then(products => {
return products.map(productData => {
return ProductsDatabase.findOneAndUpdate({
_id: xlProductData.id // or product._id
}, {
sku: xlProductData.sku,
product_name: xlProductData.product_name,
product_cost: xlProductData.product_cost,
product_price: xlProductData.product_price,
Warehouse: xlProductData.Warehouse,
product_quantity: productData.product_quantity - xlProductData.product_quantity,
$push: {
stamps: {
[new Date().getTime()]: -1 * xlProductData.product_quantity
}
},
updated_at: new Date()
}, {
upsert: false,
returnNewDocument: true
});
});
});
});
Promise.all(operations).then(() => {
console.log('All good');
}).catch(err => {
console.log('err ', err);
});
I want to exclude some fields from result.
I have code:
users = db.select('users');
users.find( {}, { sort: { points:1 }, privateKey:0, publicKey:0}, function(err,data){
res.send(data);
});
I want to exclude private and public key from results.
Can I do that using monk?
You can also do it like this:
users.find( {}, { sort: { points:1 }, fields : { privateKey:0, publicKey:0} },
function(err,data){
res.send(data);
}
);
According to documentation first argument in find is filter and second is projection .But you have used sort . It will not able to interpret . You are trying to confuse projection with sort .Sorting should be after find and projection.
You can write projection like { field1: <boolean>, field2: <boolean> ... }
Note :
The find() method always includes the _id field even if the field is not explicitly stated to return in the projection parameter.
users.find({}, { privateKey: 0, publicKey: 0 }).sort({points: 1}).toArray(
function (err, data) {
res.send(data);
});
For me, I need to use the .project() method:
const someFunction = async () => {
const result = await users
.find({}, { sort: { points: 1 })
.project({ privateKey: 0, publicKey: 0});
};
This is what worked for me for excluding the _id field.
const courseChapters = await db
.collection("users")
.find({}, { projection: { _id: 0 } })
.toArray();
So the example in the question would look something like this.
users.find(
{},
{ projection: { points: 1, privateKey: 0, publicKey: 0 } },
function (err, data) {
res.send(data);
}
);
Check out this other answer that says you may need the fields field instead of projection depending upon your driver