I have a '3-layered' relationship in MongooseJS like so, it's two one-to-many relationships between subdocuments. Like so:
var BroadcastSchema = new Schema({
...
_donationAddresses: [{
type: Schema.Types.ObjectId,
ref: 'DonationAddress'
}]
});
var DonationAddressSchema = new Schema({
...
_donations: [{
type: Schema.Types.ObjectId,
ref: 'Donation'
}]
});
var DonationSchema = new Schema({
...
amount: Number
});
I want to get the $sum total of the amount:Number on the DonationSchema
So far I've populated the Donation by using a work-around listed here (because as far as I know you can't populate a populate so far as I know)
Broadcast.find()
.exec(function(err, broadcasts) {
// this works
var iter = function(broadcast, callback) {
DonationAddress.populate(broadcast._donationAddresses, {
path: '_donations'
}, callback);
};
// tried to iterate over the donation address and
// aggregate the _donations.amount
var iter2 = function(broadcast, callback) {
DonationAddress.aggregate([{
$match: {
_id: broadcast._donationAddresses
}
}, {
$unwind: "$_donations"
}, {
$group: {
_id: "$_id",
total: {
$sum: "$_donations.amount"
}
}
}], callback);
};
async.each(broadcasts, iter, function done(err) {
async.each(broadcasts, iter2, function done(err) {
res.json(broadcasts);
});
});
Related
Two questions here.
What is the correct way to findOneAndUpdate when there is an array? The example below errors with err MongooseError [CastError]: Cast to embedded failed for value.
Should you arrays of objects become separate collections?
* Example *
var ProductSchema = new Schema({
_id: Schema.Types.ObjectId,
product_name: String
});
var purchaseOrderSchema = new Schema(
{
purchaseOrderNo: Number,
products: [ProductSchema]
}
);
const purchaseOrder = new PurchaseOrder(req.body);
PurchaseOrder.findOneAndUpdate(
{ _id: req.body._id },
{
$set: req.body,
$push: req.body.products
},
{ upsert: true, new: true }
)
.then((result) => {
console.log('result', result);
res.status(200).json(result);
})
.catch((err) => {
console.log('err', err);
res.status(500).json({ error: err });
});
const body = {
_id: 'skjdhflksjdf',
purchaseOrderNo: 1,
products: [
{
_id: '111',
product_name: 'Cup'
},
{
_id: '222',
product_name: 'Spoon'
}
]
}
In the ProductSchema the type of _id field to set to ObjectId. The product id 111 and 222 are not a valid ObjectId and it fails to cast it. You can update the type of _id in ProductSchema to Number for this to work
var ProductSchema = new Schema({
_id: Number,
product_name: String
});
i'm trying to do a pretty simple operation, pull an item from an array with Mongoose on a Mongo database like so:
User.update({ _id: fromUserId }, { $pull: { linkedUsers: [idToDelete] } });
fromUserId & idToDelete are both Objects Ids.
The schema for Users goes like this:
var UserSchema = new Schema({
groups: [],
linkedUsers: [],
name: { type: String, required: true, index: { unique: true } }
});
linkedUsers is an array that only receives Ids of other users.
I've tried this as well:
User.findOne({ _id: fromUserId }, function(err, user) {
user.linkedUsers.pull(idToDelete);
user.save();
});
But with no luck.
The second option seem to almost work when i console the lenghts of the array at different positions but after calling save and checking, the length is still at 36:
User.findOne({ _id: fromUserId }, function(err, user) {
console.log(user.linkedUsers.length); // returns 36
user.linkedUsers.pull(idToDelete);
console.log(user.linkedUsers.length); // returns 35
user.save();
});
So it looks like i'm close but still, no luck. Both Ids are sent via the frontend side of the app.
I'm running those versions:
"mongodb": "^2.2.29",
"mongoose": "^5.0.7",
Thanks in advance.
You need to explicitly define the types in your schema definition i.e.
groups: [{ type: Schema.Types.ObjectId, ref: 'Group' }],
linkedUsers: [{ type: Schema.Types.ObjectId, ref: 'User' }]
and then use either
User.findOneAndUpdate(
{ _id: fromUserId },
{ $pullAll: { linkedUsers: [idToDelete] } },
{ new: true },
function(err, data) {}
);
or
User.findByIdAndUpdate(fromUserId,
{ $pullAll: { linkedUsers: [idToDelete] } },
{ new: true },
function(err, data) {}
);
I had a similar issue. I wanted to delete an object from an array, using the default _id from mongo, but my query was wrong:
const update = { $pull: { cities: cityId }};
It should be:
const update = { $pull: { cities: {_id: cityId} }};
var PostSchema = new mongoose.Schema({
item: {
type: mongoose.Schema.ObjectId,
ref: 'item',
required: true
},
user: {
type: mongoose.Schema.ObjectId,
ref: 'User',
required: true
},
vote: {
type: Number,
default: 0
},
total: {
type: Number,
default: 0
},
awsPostKey: {type: String},
picture: {type: String, required: true}
});
var data = function(){
return Post
.find({})
.then(function(post){
return post;
})
};
var userId = //mongo objectId for current user
//postVote schema:
var PostVoteSchema = new mongoose.Schema({
post: {
type: mongoose.Schema.ObjectId,
ref: 'Post',
required: true
},
user: {
type: mongoose.Schema.ObjectId,
ref: 'User',
required: true
},
vote: {
type: Number,
default: 0
}
});
//pass data from Post query to PostVote sum function:
PostVoteSchema.statics.sum = function (data, userId) {
var postIds = data.map(function (a) {
return a._id;
});
return PostVote
.aggregate(
[
{ $match: { 'post': {$in: postIds}}},
{ $group: { _id:'$post' ,vote:{$sum:'$vote'}}}
])
.execAsync()
.then(function(votes){
return votes;
//desired output to client, _id is for specific post
{_id: 5802ea4bc00cb0beca1972cc, vote: 3, currentUserVote: -1}
});
};
I'm successfully able to get the total sum of all votes with the same postId.
Now, I"m wanting to see if the current user (userId) has placed a vote for the given post as well, then to return how they voted (+1 or -1) along with the sum of all votes for the specific post.
Is it possible to do this, or will I have to do this outside of my aggregate pipeline -- within a second query? It just seems potentially taxing to have to query the collection again.
Yes, that's possible. Within the $group pipeline, you can use the $cond operator as the logic for feeding the $sum accumulator operator. For example:
return PostVote.aggregate([
{ "$match": { "post": { "$in": postIds } } },
{
"$group": {
"_id": "$post",
"votes": { "$sum": "$vote" },
"userVotes": {
"$sum": {
"$cond": [
{ "$eq": ["$user", userId] },
"$vote",
0
]
}
}
}
}
]).execAsync().then(function(votes){
return votes;
});
I have created the following Schema:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var Player = require('./player');
var gameSchema = new Schema({
created_at: Date,
nrOfCards: String,
players: [{
sticks: String,
player: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Player'
}
}],
});
var Game = mongoose.model('Game', gameSchema);
The saving part works fine and a saved object may look something like this:
"_id": "57dd11aca0c36114588fd250",
"nrOfCards": "3",
"__v": 0,
"players": [
{
"_id": "57d415e527c20f3ed2416e05",
"age": "33"
},
{
"_id": "57d417df2186d53f3d49c996",
"age": "73"
},
{
"_id": "57d41d85ec315d4234010c7d",
"age": "20"
}
]
},
After having saved an object I would like to have it returned with the player-field populated. Here is my attempt:
app.post('/api/games', function(req, res) {
Game.create({
players : req.body.activePlayers,
nrOfCards: req.body.nrOfCards,
}, function(err, game) {
if (err) {
res.send(err);
} else {
Game.findOne(game)
.populate('players.player')
.exec(function (err, newgame) {
if (err) return handleError(err);
console.log(newgame);
res.json(newgame);
});
}
});
});
Thinking that the .populate('players.player') should do the trick , but I'm receiving the unpopulated field containing the _id of player only.
Tips appreciated. Thanks!
Use
player: {
type: Schema.Types.ObjectId,
ref: 'Player'
}
into your schema.
I have several mongoose models in my application - assignment, submisssion, and file.
var assignmentSchema = new Schema({
submissions:[{
type: mongoose.Schema.Types.ObjectId,
ref: 'Submission'
}]
});
var submissionSchema = new Schema({
assignment: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Assignment'
},
files: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'File'
}],
})
var fileSchema = new Schema({
submission: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Submission'
}
})
I defined a remove hook for assignments, so when an assignment is removed from my mongodb, all submissions are deleted too.
assignmentSchema.pre('remove', function (next) {
var assignment = this;
assignment.model('Class').update(
{_id: {$in: assignment.classes}},
{$pull: {assignments: assignment._id}},
{multi: true},
next
);
//will delete all submissions that were in the assignment
assignment.model('Submission').remove(
{_id: {$in: assignment.submissions}}).exec();
next
});
It works ok, but I also want to remove all files that are related to deleted submissions. How can I achieve this?
You have to setup a pre remove hook for your submission documents.
Then in your assignmentSchema loop through the assignment.submissions array, find each assignment document and execute a remove on that document.
Here is an example. Not tested.
assignmentSchema.pre('remove', function(nextAction) {
var assignment = this;
assignment.model('Class').update({
_id: {
$in: assignment.classes
}
}, {
$pull: {
assignments: assignment._id
}
}, {
multi: true
},
next
);
Async.each(assignment.submissions, function(subId, next) {
submissionSchema.findById(subId).exec(function(err, submission) {
submission.remove();
next();
})
}, function() {
nextAction();
})
});
submissionSchema.pre('remove', function (next) {
///remove files here.
})