I have a document in mongoDB structured like that
_id: ObjectId("generatedByMongo"),
name: {
required: true,
type: String,
trim: true
},
last: {
required: true,
type: String,
trim: true
},
grades: [{
grade: {
_id: ObjectId(""),
grade: Number,
date: date
}
}]
And to server I send array of objects containing 3 fields
[
{studentId}, {gradeId}, {newGrade}
]
What I'm trying to accomplish is I want to find in within that user collection grade with given gradeId and update it's value to newGrade. As far as I tried to do that I have done this
router.patch('/students/updateGrade',async(req,res) => {
const studentId = req.body.updateGradeArray[0].studentId;
const gradeId = req.body.updateGradeArray[0].gradeId;
const newGrade = req.body.updateGradeArray[0].newGrade;
try {
const student = await Student.find({_id: studentId})
.select({'grades': {$elemMatch: {_id: gradeId}}});
} catch(e) {
console.log(e);
}
}
);
If you intend to update just grade.grade(the number value), try this:
Student.updateOne(
// Find a document with _id matching the studentId
{ "_id": studentId },
// Update the student grade
{ $set: { "grades.$[selectedGrade].grade": newGrade } },
{ arrayFilters: [{ "selectedGrade._id": gradeId }] },
)
Why this should work:
Since you are trying to update a student document, you should be using one of MongoDB update methods not find. In the query above, I'm using the updateOne method. Inside the updateOne, I am using a combination of $set and $[identifier] update operators to update the student grade.
I hope this helps✌🏾
Related
so basically I have this and I am trying to update the STATUS part of an array.
However, everything I try does nothing. I have tried findOneAndUpdate also. I am trying to identify the specific item in the array by the number then update the status part of that specific array
(Sorry for formatting, I have no idea how to do that on the site yet ...) (Full code can be found here: https://sourceb.in/0811b5f805)
Code
const ticketObj = {
number: placeholderNumber,
userID: message.author.id,
message: m.content,
status: 'unresolved'
}
let tnumber = parseInt(args[1])
let statuss = "In Progress"
await Mail.updateOne({
"number": tnumber
}, { $set: { "status": statuss } })
Schema
const mongoose = require('mongoose')
const mailSchema = new mongoose.Schema({
guildID: { type: String, required: true },
ticketCount: { type: Number, required: true },
tickets: { type: Array, default: [] }
}, { timestamps: true });
module.exports = mongoose.model('Mail', mailSchema)
You need to use something like Mail.updateOne({"guildID": message.guild.id}, {$set: {`tickets.${tnumber}.status`: statuss}})
or for all objects in array:
Mail.updateOne({"guildID": message.guild.id}, {$set: {'tickets.$[].status': statuss}})
Also, you need to create a schema for the tickets, as it is described in docs:
one important reason to use subdocuments is to create a path where there would otherwise not be one to allow for validation over a group of fields
I am trying to locate a certain value in a sub array using Mongoose.js with MongoDB. Below is my Mongoose schema.
const foobarSchema = new mongoose.Schema({
foo: {
type: Array,
required: true
},
comments: {
type: Array,
required: false
},
createdAt: { type: Date, required: true, default: Date.now }
});
The value I am trying to get is inside foo, so in foo I always have one array at place [0] which contains an object that is like the below
{
_id
code
reason
createdAt
}
I'd like to get the value for reason for all records created in the last 30 days. I've looked around on stack overflow and haven't found anything I could piece together. Below is my existing but non working code
const older_than = moment().subtract(30, 'days').toDate();
Foobar.find({ ...idk.. req.body.reason, createdAt: { $lte: older_than }})
edit add mock document
{
foo: [{
_id: 'abc123',
code: '7a',
reason: 'failure',
createdAt: mongo time code date now
}],
comments: []
}
curent code half working
const reason = req.params.reason
const sevenAgo = moment().subtract(7, 'days').toISOString()
Foo.aggregate([
{
$match: {
"foo.createdAt": {
$gte: sevenAgo
},
"foo.reason": {
reason
}
}
},
{
$project: {
reason: {
$arrayElemAt: [
"$foo.reason",
0
]
}
}
}
])
Currently returns blank array - no query failure - which is wrong it should return at least 1 document/record as that is what is in the DB that matches
expected mock data
[
{
code: 7a,
reason: failure
}
{
code: 7a,
reason:failure
}
]
So I have something like Survey Schema (I am using mongoose).
In this Schema, for each voting option, I have votes[] array that contains ObjectIds of Users.
Now I want to check if User can vote again, or if he already voted?
The simple solution is iterating thru votes with .indexOf() and checking if id exists. Now this is a blocking way for Node JS, since this operation is sync.
Is there a way to do this with Mongo aggregate or query? So for each voting option I would get additional field like:
didIVoted: true
My Schema looks like this:
const SurveySchema = new Schema({
title: {
type: String
},
options: [{
value: String,
votes: [{ type: mongoose.Schema.Types.ObjectId, ref: 'User' }]
}]
}, { timestamps: true })
You can use $addFields and $map to overwrite existing options field. To check if userId exists in votes array you can use $indexOfArray
SurveySchema.aggregate([
{
$addFields: {
options: {
$map: {
input: "$options",
in: {
value: "$$this.value",
votes: "$$this.votes",
didIVote: { $ne: [ { $indexOfArray: [ "$$this.votes", userId ] }, -1 ] }
}
}
}
}
}
])
I am having a schema called ReferralHistory.
It contains set of users and array of referred users.
ReferralHistory
var mongoose = require('mongoose');
var refferalHistorySchema = new mongoose.Schema({
user: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User',
unique: true
},
referrals: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}],
});
var ReferralHistoryModel = mongoose.model('ReferralHistory', refferalHistorySchema);
module.exports = {
referralHistory: ReferralHistoryModel
}
I need to delete a particular user from referrals array in the collection ReferralHistory[Here i only know id of referred user].How can i achieve this?
Edit
Collection
I tried
db.referralhistories.update({ "u_referrals": "593281ef966d7f0eeb94db3d" }, { "$pull": { "u_referrals": "593281ef966d7f0eeb94db3d" } });
O/P
But document is not updating.
You use the $pull operator with .update(). So assuming referredId as the value you know
ReferralHistoryModel.update(
{ "referrals": referredId },
{ "$pull": { "referrals": referredId } },
{ "multi": true },
function(err,status) {
}
)
Noting the { "multi": true } means the update can be applied to more than one matched document in the collection. If you really only intend to match and update one document then you don't include that option since updating only the first match is the default.
If you want to be more specific and also have the "user" to match, then you can do:
ReferralHistoryModel.update(
{ "user": userId, "referrals": referredId },
{ "$pull": { "referrals": referredId } },
{ "multi": true },
function(err,status) {
}
)
And then the match needs both values to be present as opposed to any ReferralhistoryModel documents which matched the referredId you supplied.
I have two Schema defined as below:
var WorksnapsTimeEntry = BaseSchema.extend({
student: {
type: Schema.ObjectId,
ref: 'Student'
},
timeEntries: {
type: Object
}
});
var StudentSchema = BaseSchema.extend({
firstName: {
type: String,
trim: true,
default: ''
// validate: [validateLocalStrategyProperty, 'Please fill in your first name']
},
lastName: {
type: String,
trim: true,
default: ''
// validate: [validateLocalStrategyProperty, 'Please fill in your last name']
},
displayName: {
type: String,
trim: true
},
municipality: {
type: String
}
});
And I would like to loop thru each student and show it's time entries. So far I have this code which is obviously not right as I still dont know how do I join WorksnapTimeEntry schema table.
Student.find({ status: 'student' })
.populate('student')
.exec(function (err, students) {
if (err) {
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
}
_.forEach(students, function (student) {
// show student with his time entries....
});
res.json(students);
});
Any one knows how do I achieve such thing?
As of version 3.2, you can use $lookup in aggregation pipeline to perform left outer join.
Student.aggregate([{
$lookup: {
from: "worksnapsTimeEntries", // collection name in db
localField: "_id",
foreignField: "student",
as: "worksnapsTimeEntries"
}
}]).exec(function(err, students) {
// students contain WorksnapsTimeEntries
});
You don't want .populate() here but instead you want two queries, where the first matches the Student objects to get the _id values, and the second will use $in to match the respective WorksnapsTimeEntry items for those "students".
Using async.waterfall just to avoid some indentation creep:
async.waterfall(
[
function(callback) {
Student.find({ "status": "student" },{ "_id": 1 },callback);
},
function(students,callback) {
WorksnapsTimeEntry.find({
"student": { "$in": students.map(function(el) {
return el._id
})
},callback);
}
],
function(err,results) {
if (err) {
// do something
} else {
// results are the matching entries
}
}
)
If you really must, then you can .populate("student") on the second query to get populated items from the other table.
The reverse case is to query on WorksnapsTimeEntry and return "everything", then filter out any null results from .populate() with a "match" query option:
WorksnapsTimeEntry.find().populate({
"path": "student",
"match": { "status": "student" }
}).exec(function(err,entries) {
// Now client side filter un-matched results
entries = entries.filter(function(entry) {
return entry.student != null;
});
// Anything not populated by the query condition is now removed
});
So that is not a desirable action, since the "database" is not filtering what is likely the bulk of results.
Unless you have a good reason not to do so, then you probably "should" be "embedding" the data instead. That way the properties like "status" are already available on the collection and additional queries are not required.
If you are using a NoSQL solution like MongoDB you should be embracing it's concepts, rather than sticking to relational design principles. If you are consistently modelling relationally, then you might as well use a relational database, since you won't be getting any benefit from the solution that has other ways to handle that.
It is late but will help many developers.
Verified with
"mongodb": "^3.6.2",
"mongoose": "^5.10.8",
Join two collections in mongoose
ProductModel.find({} , (err,records)=>{
if(records)
//reurn records
else
// throw new Error('xyz')
})
.populate('category','name') //select only category name joined collection
//.populate('category') // Select all detail
.skip(0).limit(20)
//.sort(createdAt : '-1')
.exec()
ProductModel Schema
const CustomSchema = new Schema({
category:{
type: Schema.ObjectId,
ref: 'Category'
},
...
}, {timestamps:true}, {collection: 'products'});
module.exports = model('Product',CustomSchema)
Category model schema
const CustomSchema = new Schema({
name: { type: String, required:true },
...
}, {collection: 'categories'});
module.exports = model('Category',CustomSchema)