I have a schema that includes an array of child references:
const schemaSet = {
userSchema: new Schema({
name: {
type: String,
required: true
}
}),
groupSchema: new Schema({
name: {
type: String,
required: true
},
members: [ {
type: Schema.Types.ObjectId
ref: 'User'
}]
})
}
This is working fine in terms of being able to create groups and add users to them, but I find I can't remove a user from the group.
The closest I have got so far is this:
async removeUser(group, userId) {
console.log("Before: group has "+group.members.length+" members");
await group.members.pull({ _id : userId });
console.log("After: group has "+group.members.length+" members");
await group.save();
}
This logs out the correct size before and after the call and runs with no errors, but the next time I retrieve that group, the member is still there. I have tried using remove as well with much the same outcome.
I only want to remove the reference from the members collection, the User needs to persist. How do I persist the removal of the reference to a document?
It took me a while to discover this. If you have a group model (created using const Group = mongoose.model("Group", groupSchema)), and the id of the user you want to remove from the group, you can use the following syntax: const updatedGroup = await Group.findOneAndUpdate({ members: userId }, { $pull: { members: userId }}, {new: true, useFindAndModify: false});
The third parameter in that function indicates that the updated document should be returned, and ensures that you don't get a warning. Actually, that syntax will only work if the group to user relationship is one to many (i.e. any user can only be in one group). If the relationships is many to many, I guess you would have to use the following:
await Group.where({ members: userId}).update({ $pull: { members: userId }});
Related
I set up a small database using a model and 2 schemas.
The model goes as follows:
const userSchema = new mongoose.Schema({
friendsRequests: [friendRequestSchema],
//other credentials that are not important//
});
And the friendRequestSchema:
const friendRequestSchema = new mongoose.Schema({
from: { type: Schema.Types.ObjectId, ref: "User" },
to: { type: Schema.Types.ObjectId, ref: "User" },
});
Basically friendsRequests is an array consisting of who requested to add the user to the friends list (which is the from property) and whom the user wants to add to their friends list (which is the to property).
For the query, I am trying to sort out how to send a response without containing the users that are inside the user's friendsRequests array.
If i do this :
const recFriends = await User.findOne({ _id: req.user }).select(
"friendsRequests"
);
i will get back the array with objects containing either sent or received requests. Now i want to query again the User model and have it not return elements from this array. How would i go about doing that?
So I'm building a backend with NestJs and Typegoose, having the following models:
DEPARTMENT
#modelOptions({ schemaOptions: { collection: 'user_department', toJSON: { virtuals: true }, toObject: { virtuals: true }, id: false } })
export class Department {
#prop({ required: true })
_id: mongoose.Types.ObjectId;
#prop({ required: true })
name: string;
#prop({ ref: () => User, type: String })
public supervisors: Ref<User>[];
members: User[];
static paginate: PaginateMethod<Department>;
}
USER
#modelOptions({ schemaOptions: { collection: 'user' } })
export class User {
#prop({ required: true, type: String })
_id: string;
#prop({ required: true })
userName: string;
#prop({ required: true })
firstName: string;
#prop({ required: true })
lastName: string;
[...]
#prop({ ref: () => Department, default: [] })
memberOfDepartments?: Ref<Department>[];
static paginate: PaginateMethod<User>;
}
As you might guess, one user might be in many departments and one department can have many members(users). As the count of departments is more or less limited (compared with users), I decided to use one way embedding like described here: Two Way Embedding vs. One Way Embedding in MongoDB (Many-To-Many). That's the reason User holds the array "memberOfDepartments", but Department does not save a Member-array (as the #prop is missing).
The first question is, when I request the Department-object, how can I query members of it? The query must look for users where the department._id is in the array memberOfDepartments.
I tried multiple stuff here, like virtual populate: https://typegoose.github.io/typegoose/docs/api/virtuals/#virtual-populate like this on department.model:
#prop({
ref: () => User,
foreignField: 'memberOfDepartments',
localField: '_id', // compare this to the foreign document's value defined in "foreignField"
justOne: false
})
public members: Ref<User>[];
But it won't output that property. My guess is, that this only works for one-to-many on the one site... I also tried with set/get but I have trouble using the UserModel inside DepartmentModel.
Currently I'm "cheating" by doing this in the service:
async findDepartmentById(id: string): Promise<Department> {
const res = await this.departmentModel
.findById(id)
.populate({ path: 'supervisors', model: User })
.lean()
.exec();
res.members = await this.userModel.find({ memberOfDepartments: res._id })
.lean()
.exec()
if (!res) {
throw new HttpException(
'No Department with the id=' + id + ' found.',
HttpStatus.NOT_FOUND,
);
}
return res;
}
.. but I think this is not the proper solution to this, as my guess is it belongs in the model.
The second question is, how would I handle a delete of a department resulting in that i have to delete the references to that dep. in the user?
I know that there is documentation for mongodb and mongoose out there, but I just could not get my head arround how this would be done "the typegoose way", since the typegoose docs seem very limited to me. Any hints appreciated.
So, this was not easy to find out, hope this answer helps others. I still think there is the need to document more of the basic stuff - like deleting the references to an object when the object gets deleted. Like, anyone with references will need this, yet not in any documentation (typegoose, mongoose, mongodb) is given a complete example.
Answer 1:
#prop({
ref: () => User,
foreignField: 'memberOfDepartments',
localField: '_id', // compare this to the foreign document's value defined in "foreignField"
justOne: false
})
public members: Ref<User>[];
This is, as it is in the question, the correct way to define the virtual. But what I did wrong and I think is not so obvious: I had to call
.populate({ path: 'members', model: User })
explicitly as in
const res = await this.departmentModel
.findById(id)
.populate({ path: 'supervisors', model: User })
.populate({ path: 'members', model: User })
.lean()
.exec();
If you don't do this, you won't see the property members at all. I had problems with this because, if you do it on a reference field like supervisors, you get at least an array ob objectIds. But if you don't pupulate the virtuals, you get no members-field back at all.
Answer 2:
My research lead me to the conclusion that the best solution tho this is to use a pre-hook. Basically you can define a function, that gets called before (if you want after, use a post-hook) a specific operation gets executed. In my case, the operation is "delete", because I want to delete the references before i want to delete the document itself.
You can define a pre-hook in typegoose with this decorator, just put it in front of your model:
#pre<Department>('deleteOne', function (next) {
const depId = this.getFilter()["_id"];
getModelForClass(User).updateMany(
{ 'timeTrackingProfile.memberOfDepartments': depId },
{ $pull: { 'timeTrackingProfile.memberOfDepartments': depId } },
{ multi: true }
).exec();
next();
})
export class Department {
[...]
}
A lot of soultions found in my research used "remove", that gets called when you call f.e. departmentmodel.remove(). Do not use this, as remove() is deprecated. Use "deleteOne()" instead. With "const depId = this.getFilter()["_id"];" you are able to access the id of the document thats going to be deletet within the operation.
I am trying to ref two documents in one property, i have been checking the oficial documentation but i didn't get the solution...
At the moment i am trying this...
items: [{
type: mongoose.Schema.Types.ObjectId,
ref: ['items','users']
}],
In the documentation they mention refPath... but i could not populate both models... any solution for this?
// LINK TO DOCUMENTATION
https://mongoosejs.com/docs/populate.html#dynamic-ref
You don't need to pass refs in arrays. Here is the simple solution:
Mongoose Model (Report.js):
You can clearly see that I did not pass any ref to my Model but still, you can use multiple refs in post/get APIs. I will show you next.
const mongoose = require('mongoose');
const reportSchema = new mongoose.Schema({
reportFrom : {
type: mongoose.Schema.Types.ObjectId,
require: true,
},
reportTo: {
type: mongoose.Schema.Types.ObjectId,
require: true,
},
}
);
module.exports = mongoose.model("report", reportSchema);
Above "reportTo" means the Id of someone post whom the user is going to report or the id of user profile whom the user is going to report. Means "reportTo" may be an ID of User Profile or Post. So, if "reportTo" contains user Id then I have to refer to users collection but if "reportTo" contains post Id then I have to refer to posts collection. So, how I can use two refs. I will simply pass type query from postman to tell which ref to go either posts or users. See below my API request:
APIs file (reports.js)
const reports = req.query.type === "Post" ? await Report.find({reportTo: req.params.id}).populate({
path: 'reportFrom', // attribute name of Model
model: "User", // name of model from where you want to populate
select: "name profilePicture", // get only user name & profilePicture
}).populate({
path: 'reportTo', // attribute name of Model
model: "Post",
}).sort({ _id: -1 })
: req.query.type === "Profile" ? await Report.find({reportTo: req.params.id}).populate({
path: 'reportFrom', // attribute name of Model
model: "User",
select: "name profilePicture",
}).populate({
path: 'reportTo', // attribute name of Model
model: "User",
select: "name profilePicture",
})
.sort({ _id: -1 })
: null
return res.status(200).json(reports);
See the line 7 & 15, you can clearly see how I use two different refs for same attribute. In first case, reportTo is refered to Post Model & in second case reportTo is refered to User Model.
If a user has an array called "tags":
var User = new Schema({
email: {
type: String,
unique: true,
required: true
},
tags: [{
type: mongoose.Schema.Types.ObjectId,
ref:'Tag',
required: true
}],
created: {
type: Date,
default: Date.now
}
});
and I do a populate('tags') on a query:
User.findById(req.params.id)
.populate("tags")
.exec(function(err, user) { ... });
If one of the tags in the list has actually been deleted, is there a way to remove this dead reference in "tags"?
Currently, the returned user object IS returning the desired result -- ie. only tags that actually exist are in the tags array... however, if I look at the underlying document in mongodb, it still contains the dead tag id in the array.
Ideally, I would like to clean these references up lazily. Does anyone know of a good strategy to do this?
I've tried to find some built-in way to do that but seems that mongoose doesn't provide such functionality.
So I did something like this
User.findById(userId)
.populate('tags')
.exec((err, user) => {
user.tags = user.tags.filter(tag => tag != null);
res.send(user); // Return result as soon as you can
user.save(); // Save user without dead refs to database
})
This way every time you fetch user you also delete dead refs from the document. Also, you can create isUpdated boolean variable to not call user.save if there was no deleted refs.
const lengthBeforeFilter = user.tags.length;
let isUpdated = user.tags.length;
user.tags = user.tags.filter(tag => tag != null);
isUpdated = lengthBeforeFilter > user.tags.length;
res.send(user);
if (isUpdated) {
user.save();
}
Assuming you delete these tags via mongoose, you can use the post middleware.
This will be executed after you've deleted a tag.
tagSchema.post('remove', function(doc) {
//find all users with referenced tag
//remove doc._id from array
});
its sample retainNullValues: true
Example:
User.findById(req.params.id)
.populate({
path: "tag",
options: {
retainNullValues: true
}
})
I've got two relations in my Mongoose/MongoDB-Application:
USER:
{
name: String,
items: [{ type: mongoose.Schema.ObjectId, ref: 'Spot' }]
}
and
ITEM
{
title: String,
price: Number
}
As you can see, my user-collection containing a "has-many"-relation to the item-collection.
I'm wondering how to get all Items which are mentioned in the items-field of on specific user.
Guess its very common question, but I haven't found any solution on my own in the Docs or elsewhere. Can anybody help me with that?
If you are Storing items reference in user collection,then fetch all items from user,it will give you a array of object ids of items and then you can access all items bases on their ids
var itemIdsArray = User.items;
Item.find({
'_id': { $in: itemIdsArray}
}, function(err, docs){
console.log(docs);
});
You can get the items at the same time you query for the user, by using Mongoose's support for population:
User.findOne({_id: userId}).populate('items').exec(function(err, user) {
// user.items contains the referenced docs instead of just the ObjectIds
});