Develop Reference

Mongoose findByIdAndUpdate method not incrementing document value

I am trying to update the like count of job posts in my application using the $inc operator and the findByIdAndUpdate method from Mongoose. The correct document is being retrieved and returned but the like count for the job post never moves up from 0 and no updates are performed in the database collection.
Below is the code I am currently using to perform the update.
Jobs.findByIdAndUpdate(req.params._id , { $inc: {likes: 1}} , {new: true})
.then((ret) => {
res.send(ret)
})
Job schema
const mongoose = require('mongoose');
let JobSchema = mongoose.Schema({
student_name: {
type: String,
required: true
},
subject: {
type: String,
required: true
},
grade: {
type: Number,
required: true
},
area: {
type: String,
required: true
},
desc: {
type: String,
required: true
},
accepted: {
type: Boolean,
required: true,
default: false
},
tutor_name: {
type: String,
required: false
},
} , {collection: 'jobs'});
let Job = mongoose.model('Job' , JobSchema);
module.exports = Job;
Any insight into what is preventing the update from performing would be greatly appreciated
I have tried using two queries, one to retrieve the current likes of a post and another to manually update the doc with the incremented value. I have tried nesting the queries using .then() statements and have also tried the updateOne() and findOneAndUpdate() methods as alternatives. I have tried experimenting with the $set and $inc operators in my queries to see if either of them perform the changes, but neither do.
I am expecting the incremented 'likes' value to be reflected in the database and for the updated job document to be returned and echoed back to the console.

Your schema is missing a likes field, which means Mongoose will remove it from queries/updates (since it doesn't match the schema). Make sure to add it:
likes: {
type: Number,
default: 0
}

Can you try something like this (adding [] around update):
Jobs.findByIdAndUpdate(req.params._id , [{ $inc: {likes: 1}}] , {new: true})
.then((ret) => {
res.send(ret)
})
EDITED:
Jobs.findByIdAndUpdate(req.params._id , [{ $set: {likes: "$likes"+1}}] , {new: true})
.then((ret) => {
res.send(ret)
})

Mongoose: only one unique boolean key should be true

I have two schema collections:
Campaigns:{
_id: "someGeneratedID"
//...a lot of key value pairs.
//then i have teams which is an, array of teams from the Team schema.
teams:teams: [{ type: mongoose.Schema.Types.ObjectId, ref: "Team" }],
}
Teams:{
campaignId: { type: mongoose.Schema.Types.ObjectId, ref: "Campaign" },
isDefault: { type: Boolean, default: false },
}
Now I would like that when I add teams to the collection, it should throw an error if there are more than 2 isDefault:true per campaignId.
so the following shouldn't be allowed:
teams:[
{
campaignId:1,
teamName:"John Doe"
isDefault:true,
}
{
campaignId:1,
teamName:"Jane Doe"
isDefault:true
}
]
I found this answer on SO:
teamSchema.index(
{ isDefault: 1 },
{
unique: true,
partialFilterExpression: { isDefault: true },
}
But couldn't manage to also check for the campaignId.
Thanks in advance.
ps: can you also provide an explanation for what's happening in the index method?

I think that the simplest way to approach this is via Mongoose's middleware pre('save'). This method will give you a way to check all the campaigns listed in the collection in order to check if any of the items is already set as default.
teamSchema.pre("save", async function (next) {
try {
if ((this.isNew || this.isModified("isDefault") && this.isDefault) {
const previousDefault = await mongoose.models["Team"].findOne({ isDefault: true, campaignId: this.campaignId });
if (previousDefault) {
throw new Error('There is already default team for this campaign');
}
}
next();
} catch (error) {
throw error;
}
});
This way, if any team, either new or already existing, is set as default for a given campaign, before its record is saved, the whole collection will be searched for any entry with isDefault already set to true. If at least one item is found, we will throw an error. If not, next() guarantees the save() method will go on.

Update embedded document mongoose

I'm looking for an easy way of updating an embedded document using mongoose without having to set each specific field manually. Looking at the accepted answer to this question, once you find the embedded document that you want to update you have to actually set each respective property and then save the parent. What I would prefer to do is pass in an update object and let MongoDB set the updates.
e.g. if I was updating a regular (non embedded) document I would do this:
models.User.findOneAndUpdate({_id: req.params.userId}, req.body.user, function(err, user) {
err ? resp.status(500).send(err) : user ? resp.send(user) : resp.status(404).send();
});
Here I don't actually have to go through each property in req.body.user and set the changes. I can't find a way of doing this kind of thing with sub documents as well ?
My Schema is as follows:
var UserSchema = BaseUserSchema.extend({
isActivated: { type: Boolean, required: true },
files: [FileSchema]
});
var FileSchema = new mongoose.Schema(
name: { type: String, required: true },
size: { type: Number, required: true },
type: { type: String, required: true },
});
And I'm trying to update a file based on user and file id.
Do I need to create a helper function to set the values, or is there a MongoDB way of doing this ?
Many thanks.

Well presuming that you have something that has you "filedata" in a variable, and of course the user _id that you are updating, then you wan't the $set operator:
var user = { /* The user information, at least the _id */
var filedata = { /* From somewhere with _id, name, size, type */ };
models.User.findOneAndUpdate(
{ "_id": user._id, "files._id": filedata._id },
{
"$set": {
"name": filedata.name,
"size": filedata.size,
"type": filedata.type
}
},
function(err,user) {
// Whatever in here such a message, but the update is already done.
}
);
Or really, just only $set the fields that you actually mean to "update" as long as you know which ones you mean. So if you only need to change the "size" then just set that for example.

MongoDB query on populated fields

I have models called "Activities" that I am querying for (using Mongoose). Their schema looks like this:
var activitySchema = new mongoose.Schema({
actor: {
type: mongoose.Schema.ObjectId,
ref: 'User',
required: true
},
recipient: {
type: mongoose.Schema.ObjectId,
ref: 'User'
},
timestamp: {
type: Date,
default: Date.now
},
activity: {
type: String,
required: true
},
event: {
type: mongoose.Schema.ObjectId,
ref: 'Event'
},
comment: {
type: mongoose.Schema.ObjectId,
ref: 'Comment'
}
});
When I query for them, I am populating the actor, recipient, event, and comment fields (all the references). After that, I also deep-populate the event field to get event.creator. Here is my code for the query:
var activityPopulateObj = [
{ path: 'event' },
{ path: 'event.creator' },
{ path: 'comment' },
{ path: 'actor' },
{ path: 'recipient' },
{ path: 'event.creator' }
],
eventPopulateObj = {
path: 'event.creator',
model: User
};
Activity.find({ $or: [{recipient: user._id}, {actor: {$in: user.subscriptions}}, {event: {$in: user.attending}}], actor: { $ne: user._id} })
.sort({ _id: -1 })
.populate(activityPopulateObj)
.exec(function(err, retrievedActivities) {
if(err || !retrievedActivities) {
deferred.reject(new Error("No events found."));
}
else {
User.populate(retrievedActivities, eventPopulateObj, function(err, data){
if(err) {
deferred.reject(err.message);
}
else {
deferred.resolve(retrievedActivities);
}
});
}
});
This is already a relatively complex query, but I need to do even more. If it hits the part of the $or statement that says {actor: {$in: user.subscriptions}}, I also need to make sure that the event's privacy field is equal to the string public. I tried using $elemMatch, but since the event has to be populated first, I couldn't query any of its fields. I need to achieve this same goal in multiple other queries, as well.
Is there any way for me to achieve this further filtering like I have described?

The answer is to change your schema.
You've fallen into the trap that many devs have before you when coming into document database development from a history of using relational databases: MongoDB is not a relational database and should not be treated like one.
You need to stop thinking about foreign keys and perfectly normalized data and instead, keep each document as self-contained as possible, thinking about how to best embed relevant associated data within your documents.
This doesn't mean you can't maintain associations as well. It might mean a structure like this, where you embed only necessary details, and query for the full record when needed:
var activitySchema = new mongoose.Schema({
event: {
_id: { type: ObjectId, ref: "Event" },
name: String,
private: String
},
// ... other fields
});
Rethinking your embed strategy will greatly simplify your queries and keep the query count to a minimum. populate will blow your count up quickly, and as your dataset grows this will very likely become a problem.

You can try below aggregation. Look at this answer: https://stackoverflow.com/a/49329687/12729769
And then, you can use fields from $addFields in your query. Like
{score: {$gte: 5}}

but since the event has to be populated first, I couldn't query any of its fields.
No can do. Mongodb cannot do joins. When you make a query, you can work with exactly one collection at a time. And FYI all those mongoose populates are additional, distinct database queries to load those records.
I don't have time to dive into the details of your schema and application, but most likely you will need to denormalize your data and store a copy of whatever event fields you need to join on in the primary collection.

Mongoose embedded document updating

I have a problem with embedded document update.
My defined Schemas:
var Talk = new Schema({
title: {
type: String,
required: true
},
content: {
type: String,
required: true
},
date: {
type: Date,
required: true
},
comments: {
type: [Comments],
required: false
},
vote: {
type: [VoteOptions],
required: false
},
});
var VoteOptions = new Schema({
option: {
type: String,
required: true
},
count: {
type: Number,
required: false
}
});
Now I would like to update vote.count++, with given Talk id and VoteOption id. I have the following function to do the job:
function makeVote(req, res) {
Talk.findOne(req.params.id, function(err, talk) {
for (var i = 0; i < talk.vote.length; i++) {
if (talk.vote[i]._id == req.body.vote) {
talk.vote[i].count++;
}
}
talk.save(function(err) {
if (err) {
req.flash('error', 'Error: ' + err);
res.send('false');
} else {
res.send('true');
}
});
});
}
Everything executes, I get back the res.send('true'), but the value on count does not change.
When I did some console.log I saw that it changed the value, but the talk.save just doesn't save it in db.
Also I'm quite unhappy about the cycle just to find _id of embedded doc. In the mongoose documentation I read about talk.vote.id(my_id) but that gives me error of not having an id function.

When updating a Mixed type (which seems to be anything else than a basic type, so that also includes embedded documents), one has to call .markModified on the document. In this case, it would be:
talk.markModified("vote"); // mention that `talk.vote` has been modified
talk.save(function(err) {
// ...
});
Hope this helps someone in the future since I couldn't find the answer very quickly.
Reference:
... Mongoose loses the ability to auto detect/save those changes. To "tell" Mongoose that the value of a Mixed type has changed, call the .markModified(path) method of the document passing the path to the Mixed type you just changed.

It's because you are trying to save your talk object before the callback which increments count has been fired. Also, did you make sure to instantiate your Talk schema? eg:
var talk = new Talk();
However, if all you want to do is increment your count variable, mongo supports atomic, in-place updates which you may find useful:
talk.find( { _id : req.body.vote }, { $inc: { count : 1 } } );
have a look at:
http://www.mongodb.org/display/DOCS/Updating#Updating-%24inc