I've been reading a few answers regarding this and yet I still can't get it to work.
My model objects aren't deeply nested and are quite simple. It's events that have a list of users attending them and users that have a list of events they've attended. like so:
let DinnerSchema = new mongoose.Schema({
date: {
type: Date,
unique: true,
timestamps: true,
required: true
},
title:{type: String, require: true},
attending: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}]
})
and the users:
let UserSchema = new mongoose.Schema({
email: {
type: String,
lowercase: true,
unique: true,
required: true
},
name:{ type: String, require: true },
password: {type: String ,required: true},
dinners: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'Dinner'
}]
})
And for clarity here's the entire route that's using populate:
userpage.get('/', authCheck, (req, res) => {
const options = { _id: '57ebbf48bd6914036f99acc7' }
return Dinner
.findOne(options)
.populate('User', 'name') //I'VE TRIED ADDING 'name' BASED ON SOME ANSWERS I SAW
.exec((err, newDinner) => {
if (err) {
console.log(err)
res.status(400).end()
}
console.log(newDinner) // SHOW'S USERS ID'S BUT NO OTHER FIELDS
return res.json({
sucsess: true,
data: newDinner
})
})
})
If I understand correctly in the database itself there should only be a reference to the other model and not actually all of it's fields and the join happens with the populate. My db structure show's just the reference so that's ok.
I've tried specifying the name of the fields i'm after (the name field in this case) but that didn't work.
My population result always looks like the following and doesn't show any other fields except for the _id one:
{
_id: 57ebbf48bd6914036f99acc7,
date: 2016-09-27T22:00:00.000Z,
title: '1',
__v: 0,
attending: [ 57ebbcf02c39997f9cf26891, 57ebbdee098d3c0163db9905 ]
}
What am I screwing up here?
In mongoose populate receives 4 parameters.
path
selection(fields to be return) ,
condition
options (like {limit:10})
In your case you are not passing right path to populate. It should be
userpage.get('/', authCheck, (req, res) => {
const options = { _id: '57ebbf48bd6914036f99acc7' }
return Dinner
.findOne(options)
.populate('attending', 'name')
.exec((err, newDinner) => {
if (err) {
console.log(err)
res.status(400).end()
}
console.log(newDinner) // SHOW'S USERS ID'S BUT NO OTHER FIELDS
return res.json({
sucsess: true,
data: newDinner
})
})
})
Now it will return all the names of attending users.
you need to populate attending - that's your user reference in the dinner schema
Related
My service uses MongoDB and Mongoose. I have two DBs: Users and Posts. In Posts schema I have parameters:
"author", that contains userId from Users DB
"anonymous", a boolean-parameter that shows if the post is anonymous or not.
I can't solve the problem: when I request data from Posts DB I want to populate author in the "author" parameter only for non-anonymous posts, for anonymous ones I'd like to return null or not to return this parameter at all.
I've tried to use "match", but it doesn't work.
How can I solve this problem?
Thank you.
Code example:
const postSchema = mongoose.Schema(
{
author: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: 'User',
},
anonymous: {
type: Boolean,
required: true,
default: false,
},
content: {
type: String,
required: true,
},
date: {
type: Date,
required: true,
default: Date.now,
},
},
{
timestamps: true,
}
);
For population I use pre:
postSchema.pre(/^find/, function (next) {
this.populate({
path: 'author',
select: '_id login',
});
next();
});
I am working with node(express) with mongoose and I have two collections,
Users
Comments
I added the sample Schema(added few fields only)
const UserSchema = mongoose.Schema({
name: String,
email: String,
});
const CommentsSchema = mongoose.Schema({
comments: String,
user_id: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
},
text: String,
});
So I trying to fetch the users list and no of comments count based on user..
Expecting output like below:
data = [
{
name: 'abcd',
email: 'aa#test.com',
commentsCount: 5
},
{
name: 'xxx',
email: 'xx#test.com',
commentsCount: 3
}
]
I am not sure how to get the results, because we don;t have ref in user table..
userModel.find({}).exec((err, users) => {
if (err) {
res.send(err);
return;
}
users.forEach(function(user){
commentsModel.countDocuments({user_id: users._id}).exec((err, count) => {
if(!err){
user.commentsCount = count;
}
})
});
console.log('users', users)
});
Can you anyone please help to fix, I needs to list out the users and count of comments
What I want is that a user can like a post only once, hence I uniquely indexed the user in the likes array to ensure the same, but it isn't working and I can't find out what is wrong here .
The schema looks like this :
const mongoose = require('mongoose')
const postSchema = new mongoose.Schema({
author: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User' // User model
},
text: {
type: String,
required: [true, 'Post must have some text']
},
likes: [
{
user: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}
}
],
comments: [
{
author: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
},
text: {
type: String,
required: [true, 'Comment must have some text']
},
addedAt: {
type: Date,
default: Date.now
}
}
],
createdAt: {
type: Date,
default: Date.now
}
})
postSchema.pre(/^find/, function(next) {
this.populate({
path: 'author',
select: 'name avatar'
}).populate({
path: 'comments.author',
select: 'name avatar'
})
next()
})
// Ensure a user can like a post only once
postSchema.index({ 'likes.user': 1 }, { unique: true })
const Post = mongoose.model('Post', postSchema)
module.exports = Post
However when I send a post request to like a post twice via the same user it
shows no error.
Here is the postman output
I have tried both the ways listed in this, but none of them worked in this case.
Mongoose Index on a field in nested document
How do I ensure a user can like a post only once from the schema itself ?
Try saving likes in this format in the database
likes:[{type:mongoose.Schema.Types.ObjectId,ref: 'User'}]
making it
likes:[ObjectId("5af03111967c60501d97781f")]
and when the post like API is hit do
{$addToSet: {likedBy: userId}}
in update query,addToSet ensures no duplicate ids are maintained in the array.
**I have answered below. In short you need to require the Model in the module in which you wish to populate, even though you do not refer to it directly.
I am hitting a strange problem with mongoose when populating just one particular array of IDs.
I have three models, User, Company and Widgets.
When I return the company populated with the users all is fine using:
Company.findOne({ name: 'xyz' })
.populate('users')
.exec(function(err, company) {
if (err) return res.send(err)
res.send(company)
})
However when I try to replace populate 'users' with 'widgets' I get the following error:
{
"message": "Schema hasn't been registered for model \"widget\".\nUse mongoose.model(name, schema)",
"name": "MissingSchemaError"
}
Here are the models:
USER:
const UserSchema = new Schema({
name: String,
email: {
type: String,
unique: true,
required: true
},
password: {
type: String,
required: true
},
company: {
type: Schema.Types.ObjectId,
ref: 'company'
}
});
const User = mongoose.model("user", UserSchema);
COMPANY:
const CompanySchema = new Schema({
name: String,
URL: {
type: String,
unique: true
},
users: [{
type: Schema.Types.ObjectId,
ref: 'user'
}],
widgets: [{
type: Schema.Types.ObjectId,
ref: 'widget'
}]
});
const Company = mongoose.model('company', CompanySchema);
WIDGET:
const WidgetSchema = new Schema({
title: {
type: String,
required: true
},
maker: String
});
const Widget = mongoose.model('widget', WidgetSchema);
I have manually inspected the _ids in the widget array of the company model and they are all correct.
OK, so this was a lack of understanding on my behalf.
In the module where I was using:
Company.findOne({ name: 'xyz' })
.populate('users')
.exec(function(err, company) {
if (err) return res.send(err)
res.send(company)
})
I had imported the User model for other uses in the module. However, as I was not directly referring to Widget I had not imported it. Having done some more research I found that you need to import a model when populating even though not referring to it directly.
Let me know if best to delete whole thread or leave for reference.
When the user visits a certain page of my App, the Component dispatches an action to fetch information. Namely, the action performs the following operations:
Base.find({req.params.id})
BaseUser.find({ baseId: req.params.id }) **returns multiple docs**
Message.find({ baseId: req.params.id }) **returns multiple docs**
The operation happens in this order. I could query the first one via .findById, but for uniformity of the problem I chose .find(). The problem now is that the results of
Promise.all([
Base.find({ _id: req.params.id }),
BaseUser.find({ baseId: req.params.id }),
Message.find({ baseId: req.params.id })
])
come in an array, like so:
[
[ { created: 2018-08-29T23:59:35.380Z,
_id: 5b8741151985662f10d04fdb,
creatorId: 5b86f7970cd98b2004969bf0,
title: 'testBase1',
} ],
[ { created: 2018-08-30T00:57:57.764Z,
acceptedMembership: true,
isCreator: true,
_id: 5b8741151985662f10d04fdc,
userId: 'tester1',
baseId: 5b8741151985662f10d04fdb }
],
[ { created: 2018-08-30T00:58:09.182Z,
_id: 5b8741211985662f10d04fdd,
baseId: 5b8741151985662f10d04fdb,
content: 'testMessage1' }
]
]
This quite obviously causes problems when further trying to map/filter/res.json() the data. Is there any known way to return this in a single array, or even better, pass it to the front-end (redux action) as an object? Does anyone know of a better solution which handles this problem slightly differently, and prevents me from fetching each of those methods on subcomponents ?
update:
I have now constructed this, which is fairly ugly to look at:
let completeObject = {
base: {},
users: [],
messages: []
};
Base.findById(req.params.id)
.then(data => {
completeObject.base = data;
return data;
})
.then(data => {
BaseUser.find({ baseId: req.params.id })
.then(data => {
completeObject.users = data;
return data;
})
.then(data => {
Message.find({ baseId: req.params.id }).then(data => {
completeObject.messages = data;
return res.json(completeObject);
});
});
})
Why don't you setup ref in the Base model to the BaseUser and Message and then use populate to fill those arrays and get one object as result filled with the arrays of BaseUser and Message?
From what I see you key on the req.params.id which means you have a cross-reference between those collections anyway.
Here is an example:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var BaseSchema = Schema({
_id: Schema.Types.ObjectId,
creatorId: Schema.Types.ObjectId,
title: String,
users: [{ type: Schema.Types.ObjectId, ref: 'User' }],
messages: [{ type: Schema.Types.ObjectId, ref: 'Message' }],
});
var UserSchema = Schema({
_id: Schema.Types.ObjectId,
acceptedMembership: Boolean,
isCreator: Boolean,
userId: String,
baseId: Schema.Types.ObjectId
});
var MessageSchema = Schema({
_id: Schema.Types.ObjectId,
baseId: Schema.Types.ObjectId,
content: String
});
var Base = mongoose.model('Base', BaseSchema);
var User = mongoose.model('User', UserSchema);
var Message = mongoose.model('Message', MessageSchema);
Now that the schemas are defined (and you added some records) you could find a Base by _id and populate users and messages:
Base.
findOne({ _id: req.params.id }).
populate('users').
populate('messages').
exec(function (err, base) {
if (err) return handleError(err);
console.log(base);
});
You should check the mongoose documentation on how to save / populate references etc.