I've got a Mongoose schema set up as follows:
const mongoose = require('mongoose');
const TodoSchema = mongoose.Schema({
id: {
type: String,
required: true,
},
todos: {
type: Array,
required: true,
},
date: {
type: Date,
default: Date.now(),
},
});
module.exports = mongoose.model('todo', TodoSchema, 'todos');
Each of the elements in the todos Array is an Object and has the following format (example):
{
id: 1,
todo: "Do the dishes."
category: "Kitchen"
}
There are multiple documents in my Todo collection and they all contain the same list of Todos. If I wanted to update a specific Todo across ALL documents, I figure I need to use updateMany. I'm using the following in my Todo Update route to update all instances of a Todo:
const { todo } = req.body; // todo.todo contains "Clean the dishes." as an update
Todo.updateMany(
{
todos: { $elemMatch: { id: todo.id } },
},
{ $set: { todo: todo } }
);
I'm assigning the result of the above route code to a variable and console logging the result which comes back with:
{ ok: 0, n: 0, nModified: 0 }
What am I doing wrong? The passed todo id matches the id of a Todo in each of the Todos arrays.
First of all, for your object array, is recommendable create a schema too:
const subSchema = new mongoose.Schema({
id: Number,
todo: String,
category: String
})
const MongooseModel = new mongoose.Schema({
id: String,
todos: [subSchema],
date: Date
})
So now, your array object is defined.
And, the query question is something like that:
db.collection.update({
"todos.id": todo.id
},
{
"$set": {
"todos.$": {newTodo}
}
},
{
"multi": true
})
First, you look for all elements that match your criteria; that is: todos.id = todo.id, then you use $ operator to set all element that match the criteria with your object.
The last line multi is to updated all element that match.
Example playground here
Using moongoose, multi attribute is not neccessary because is set true by default using updateMany().
So moongose query should be something like that.
var update = await model.updateMany(
{
"todos.id": 1
},
{
"$set": {
"todos.$": {
"id": 20,
"todo": "newTodo",
"category": "newCategory"
}
}
})
And for this example data the result is
{ n: 3, nModified: 3, ok: 1 }
Related
I'm new to MongoDB, and I'm trying to do a very simple task, but however I can't get it right.
What I want is to change the process status but I tried "FindAndUpdate", "UpdateOne" and "FindByIdAndUpdate" but it won't work.
Maybe it has to do with my Schema. Should I create a new Schema for the Process?
My Database entry inside a MongoDB Collection:
_id: 622c98cfc872bcb2578b97a5
username:"foo"
__v:0
process:Array
0: Object
processname:"bar"
process_status:"stopped"
_id: 6230c1a401c66fc025d3cb88
My current Schema:
const User = new mongoose.Schema(
{
username: { type: String, required: true },
process: [
{
processname: {
type: String,
},
process_status: {
type: String,
},
},
],
},
{ collection: "user-data" }
);
My current code:
const startstopprocess = await User.findByIdAndUpdate(
{ _id: "6230c1a401c66fc025d3cb88" },
{ process_status: "started" }
).then(function (error, result) {
console.log(error);
console.log(result);
});
You can use positional operator $ in this way:
db.collection.update({
"process._id": "6230c1a401c66fc025d3cb88"
},
{
"$set": {
"process.$.process_status": "started"
}
})
Note how using positional operator you can say mongo "from the object you have found in find stage, update the process_status variable to started"
Example here
I'm new to Aggregation in MongoDB and I'm trying to understand the concepts of it by making examples.
I'm trying to paginate my subdocuments using aggregation but the returned document is always the overall values of all document's specific field.
I want to paginate my following field which contains an array of Object IDs.
I have this User Schema:
const UserSchema = new mongoose.Schema({
username: {
type: String,
unique: true,
required: true
},
firstname: String,
lastname: String,
following: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}],
...
}, { timestamps: true, toJSON: { virtuals: true }, toObject: { getters: true, virtuals: true } });
Without aggregation, I am able to paginate following,
I have this route which gets the user's post by their username
router.get(
'/v1/:username/following',
isAuthenticated,
async (req, res, next) => {
try {
const { username } = req.params;
const { offset: off } = req.query;
let offset = 0;
if (typeof off !== undefined && !isNaN(off)) offset = parseInt(off);
const limit = 2;
const skip = offset * limit;
const user = await User
.findOne({ username })
.populate({
path: 'following',
select: 'profilePicture username fullname',
options: {
skip,
limit,
}
})
res.status(200).send(user.following);
} catch (e) {
console.log(e);
res.status(500).send(e)
}
}
);
And my pagination version using aggregate:
const following = await User.aggregate([
{
$match: { username }
},
{
$lookup: {
'from': User.collection.name,
'let': { 'following': '$following' },
'pipeline': [
{
$project: {
'fullname': 1,
'username': 1,
'profilePicture': 1
}
}
],
'as': 'following'
},
}, {
$project: {
'_id': 0,
'following': {
$slice: ['$following', skip, limit]
}
}
}
]);
Suppose I have this documents:
[
{
_id: '5fdgffdgfdgdsfsdfsf',
username: 'gagi',
following: []
},
{
_id: '5fgjhkljvlkdsjfsldkf',
username: 'kuku',
following: []
},
{
_id: '76jghkdfhasjhfsdkf',
username: 'john',
following: ['5fdgffdgfdgdsfsdfsf', '5fgjhkljvlkdsjfsldkf']
},
]
And when I test my route for user john: /john/following, everything is fine but when I test for different user which doesn't have any following: /gagi/following, the returned result is the same as john's following which aggregate doesn't seem to match user by username.
/john/following | following: 2
/kuku/following | following: 0
Aggregate result:
[
{
_id: '5fdgffdgfdgdsfsdfsf',
username: 'kuku',
...
},
{
_id: '5fgjhkljvlkdsjfsldkf',
username: 'gagi',
...
}
]
I expect /kuku/following to return an empty array [] but the result is same as john's. Actually, all username I test return the same result.
I'm thinking that there must be wrong with my implementation since I've only started exploring aggregation.
Mongoose uses a DBRef to be able to populate the field after it has been retrieved.
DBRefs are only handled on the client side, MongoDB aggregation does not have any operators for handling those.
The reason that aggregation pipeline is returning all of the users is the lookup's pipeline does not have a match stage, so all of the documents in the collection are selected and included in the lookup.
The sample document there is showing an array of strings instead of DBRefs, which wouldn't work with populate.
Essentially, you must decide whether you want to use aggregation or populate to handle the join.
For populate, use the ref as shown in that sample schema.
For aggregate, store an array of ObjectId so you can use lookup to link with the _id field.
I am trying to add tags to existing tags in a MongoDB collection with this Schema:
const workSchema = new mongoose.Schema({
title: {
type: String,
required: "Tile can't be blank"
},
description: {
type: String
},
imageURL: {
type: String,
unique: true
},
workURL:{
type: String,
unique: true
},
tags:{
type:Array
},
createdDate: {
type: Date,
default: Date.now
}
});
const Work = mongoose.model('Work', workSchema);
module.exports = Work;
I made an API that makes a PUT request to "/api/work/:workId/tags"
exports.updateTags = (req, res) =>{
try{
const newTags = req.body.tags.split(',');
newTags.forEach(tag => {
db.Work.update(
{"_id": req.params.workId},
{
$push:{
tags: tag
}
}
)
})
res.status(200).send({message : "tags updated"})
}
catch(error){
res.status(400).send(error)
}
}
request.body:
{
tags:"a,b,c"
}
The problem is that the array won't update with the new tag values
I searched for other ways to update in the docs and on the web but I didn't find any solutions.
You haven't defined _id in your workSchema so the type of _id would be ObjectId
But req.params.workId is probably a String, so querying an ObjectId with a String won't work.
So you should convert req.params.workId to ObjectId using mongoose.Types.ObjectId
{ "_id": mongoose.Types.ObjectId(req.params.workId) }
But you can improve your code a bit more by using .findByIdAndUpdate and $each operator
.findByIdAndUpdate will automatically convert your _id to ObjectId
You can use $each to $push multiple array elements at the same time without using .forEach
Work.findByIdAndUpdate(req.params.workId, {
$push: { "tags": { $each: newTags } }
})
I have a Mongoose document (Mongoose 5.4.13, mongoDB 4.0.12):
var SkillSchema = new mongoose.Schema({
skill: { type: String },
count: { type: Number, default: 0 },
associatedUsers: [{ type : mongoose.Schema.Types.ObjectId, ref: 'User' }]
});
That I update as follows:
var query = { skill: req.body.skill };
var update = { $addToSet: { associatedUsers: req.params.id } };
var options = { upsert: true, new: true, setDefaultsOnInsert: true };
await skillSchema.findOneAndUpdate(query, update, options);
During this update, I would like to also update count to be equal to the length of associatedUsers.
Ideally I want this to happen at the same time as updating the other fields (i.e not in a subsequent update), either via a pre-hook or within findOneAndUpdate.
I've tried using a pre hook after schema definition:
SkillSchema.pre('findOneAndUpdate', async function(){
console.log("counting associated users");
this.count = this.associatedUsers.length;
next();
});
As well as using aggregate in my UPDATE route:
await skillSchema.aggregate([{ $project: { count: { $size: "$associatedUsers" } } } ])
But I can't get either to work.
Does anyone have any suggestions for how I could achieve this?
You could use $set like this in 4.2 which supports aggregation pipeline in update.
The first $set stage calculates a associatedUsers based on the previous and new value. $setUnion to keep the distinct associatedUsers values.
The second $set stage calculates tally based on the associatedUsers calculated in the previous stage.$size to calculate the length of associatedUsers values.
var query = {skill: req.body.skill};
var update = [{ $set: { "associatedUsers":{"$setUnion":[{"$ifNull":["$associatedUsers",[]]}, [req.params.id]] }}}, {$set:{tally:{ $size: "$associatedUsers" }}}];
var options = { upsert: true, new: true, setDefaultsOnInsert: true };
await skillSchema.findOneAndUpdate(query, update, options)
If any argument resolves to a value of null or refers to a field that is missing, $setUnion returns null. So just needed to safeguard our operation with $ifNull
About tally and associatedUsers.length
// define your schema object
var schemaObj = {
skill: { type: String },
associatedUsers: { type: Array }
};
// get the length of users
var lengthOfAsUsers = schemaObj.associatedUsers.length;
// add tally to schema object and set default to the length of users
schemaObj.tally = { type: Number, default: lengthOfAsUsers };
// and pass your schema object to mongoose.Schema
var SkillSchema = new mongoose.Schema(schemaObj);
module.exports = SkillSchema;
EDIT
you can update tally subsequently, but recommended solution would be to use this method
https://mongoosejs.com/docs/populate.html
const id = "nameSomeId";
SkillSchema.find({ _id: id }).then(resp => {
const tallyToUpdate = resp.associatedUsers.length;
SkillSchema.findOneAndUpdate({ _id: id }, { tally: tallyToUpdate }).then(
resp => {
console.log(resp);
}
);
});
The solution I have will only work on mongodb v 4.2 as it has option to use aggregate in the update and will only need one query as:
skillSchemafindOneAndUpdate(
{skill:"art"},
[
{ $set: {
associatedUsers:{
$cond:{
if: {$gte: [{$indexOfArray: ["$associatedUsers", mongoose.Types.ObjectId(req.params.id)]}, 0]},
then: "$associatedUsers",
else: { $cond:{
if: { $isArray: "$associatedUsers" },
then: {$concatArrays:["$associatedUsers",[mongoose.Types.ObjectId(req.params.id)]]},
else: [mongoose.Types.ObjectId(req.params.id)]
}}
}
}}},
{$set:{
associatedUsers:"$associatedUsers",
tally:{$size:"$associatedUsers"},
}}
],
{upsert:true,new:true}
)
ref: https://docs.mongodb.com/manual/reference/method/db.collection.update/#update-with-aggregation-pipeline
The "Group" field does not appear in the schema. On MongoDB Shell, these codes will work.
However, Mongoose will also give an error because the schema is validated.
Is the "Group" field a dynamic field? I think the problem with the schema will be solved.
var mongoose = require("mongoose");
var SkillSchema = new mongoose.Schema({
skill: { type: String },
tally: { type: Number, default: 0 },
associatedUsers: { type: Array },
group: { type: Array }
});
I have a Mongoose collection of which I want to update a nested subdocument.
The basic setup is this:
a parent entry (Map)
which contains an array of children (Phases)
each child consists of one or more grandchildren (Steps).
I want to be able to find a grandchild and update it. My approach is to find the parent (Map) that contains the grandchild and then update it.
These are my simplified schemas:
const phaseSchema = new mongoose.Schema(
{
name: String,
color: String,
steps: [
new mongoose.Schema(
{
name: String,
body: String,
entry: {
type: mongoose.SchemaTypes.ObjectId,
ref: 'entry',
default: null
}
},
{ timestamps: false }
)
]
},
{ timestamps: false, _id: true }
)
const mapSchema = new mongoose.Schema(
{
name: String,
phases: [phaseSchema]
},
{ timestamps: false }
)
export const Map = mongoose.model('map', mapSchema)
I'm trying to use ArrayFilters to find and update the subdocument, but to no luck:
req.body = {
map_id: 'some_mongoose_id',
step_id: 'some_other_mongoose_id'
}
const newEntryId = 'a_new_mongoose_id'
// Find the parent (Map) and update it
const UpdatedMap = await Map.update(
{ _id: req.body.map_id },
{
$set: {
'phases.$[i].steps.$[j].entry': mongoose.Types.ObjectId(newEntryId)
}
},
{
arrayFilters: [
{
'i.steps._id': mongoose.Types.ObjectId(req.body.step_id)
},
{
'j._id:': mongoose.Types.ObjectId(req.body.step_id)
}
]
}
)
This throws the following error:
Error: Could not find path "phases.0.steps.0._id:" in schema
Coincidentally, the phase and step I'm trying to update are both at index 0.
If I swap out the arrayFilters and hardcode the indexes, like so $set: {'phases.0.steps.0.entry': mongoose.Types.ObjectId(newEntryId)'}, it works.
What am I doing wrong?
The i is what's causing the error and it's also redundant. the nested arrayFilter will work as required without it.
const UpdatedMap = await Map.update(
{ _id: req.body.map_id },
{
$set: {
'phases.steps.$[j].entry': mongoose.Types.ObjectId(newEntryId)
}
},
{
arrayFilters: [
{
'j._id:': mongoose.Types.ObjectId(req.body.step_id)
}
]
}
)