I have an array of posts and each post contains an author id. I want to loop through each post and find author from User model by using author id and then attach it to post. What is the best and efficient way to do it. I am currently doing it this way, but it decreases the performance. Thanks.
posts = await Promise.all(
posts.map(async post => {
post.author = await User.findById(post.author).lean();
return post;
})
);
// POST SCHEMA
const postSchema = new mongoose.Schema({
author: {
type: String,
required: true
},
body: {
type: String,
required: true
},
post_image: {
url: String,
public_id: String,
width: Number,
height: Number
},
date_created: {
type: Date,
default: Date.now()
}
});
// USER SCHEMA
const userSchema = new mongoose.Schema({
name: {
type: String,
required: true
},
email: {
type: String,
required: true,
unique: true
},
password: {
type: String,
required: true
},
register_date: {
type: Date,
required: true,
default: Date.now()
},
friends: {
type: Array,
default: []
}
});
// NEW POST SCHEMA
const postSchema = new mongoose.Schema({
author: {
type: mongoose.Schema.Types.ObjectId,
ref: 'users',
required: true
},
body: {
type: String,
required: true
},
post_image: {
url: String,
public_id: String,
width: Number,
height: Number
},
date_created: {
type: Date,
default: Date.now()
}
});
// USER SCHEMA
const userSchema = new mongoose.Schema({
name: {
type: String,
required: true
},
email: {
type: String,
required: true,
unique: true
},
password: {
type: String,
required: true
},
register_date: {
type: Date,
required: true,
default: Date.now()
},
friends: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'users',
required: true
}],
});
You can use auto population of mongo object in mongoose. It won't cause performance issues as it uses id index. Similar to this doc: https://mongoosejs.com/docs/populate.html
Your query will look like this:
const post = await Post.find({ author: { $in: req.user.friends }})
.populate('author')
.exec();
console.log(post);
Or you can use aggregate according to this document: https://mongoosejs.com/docs/api/aggregate.html
Your query will then look like:
const query = [
{ $match: { author: { $in: req.user.friends } } },
{ $lookup: { from: "users", localField: "author", foreignField: "_id", as: "authorDetails" } },
{ $unwind: "authorDetails" },
]
const post = await Post.aggregate(query).exec();
console.log(post);
Related
I have two mongoose db schemas as follows
Posts schema
return model('post',
Schema({
title: {
type: String,
required: true
},
content: {
type: String,
required: true
},
createdBy: {
type: Types.ObjectId,
ref:"user"
},
},
{ timestamps: true })
);
Like schema
return model('like',
Schema({
userId: {
type: Types.ObjectId,
required: true,
ref: "user"
},
postId: {
type: Types.ObjectId,
required: true,
ref: "post"
}
},
{ timestamps: true })
);
how to populate like documents with post documents?i also want to consider the case where a post not have a like schema at all.
How can I add a User to the School's admins field?
School Schema:
const School = new Schema({
name: { type: String, required: true },
grades_primary: [{ type: Schema.Types.ObjectId, ref: 'Grade' }],
grades_secondary: [{ type: Schema.Types.ObjectId, ref: 'Grade' }],
admins: [{ type: Schema.Types.ObjectId, ref: 'User' }]
})
User Schema
const User = new Schema({
complete_name: { type: String, required: true, },
password: { type: String, required: true },
nombre_de_usuario: { type: String, unique: true, required: true },
email: { type: String, unique: true, required: true },
})
I tried this but it didn't work:
const saved_user = await user.save()
created_school.admins.push(saved_user)
await created_school.save()
use $push
const saved_user = await user.save()
try {
const created_school= await School.findOneAndUpdate({ _id: '1' }, { $push: { admins: saved_user } })
// ....
} catch (error) {
console.log(error);
}
So the example right now is for the User table.. I have a UserWeapon document embedded that is an array of all the weapon's a user has and how many kills they have with the weapon. I want to write a query that when given the userId, weaponId, and new kills, it'll update the sub document accordingly.
So something like
const user = await User.findById(userId);
const userWeapon = await user.userWeapon.findById(weaponId);
userWeapon.kills = userWeapon.kills + newAmmountOfKills
user.save();
What would be the most efficient way to do this?
Schemas:
const UserWeaponSchema = new Schema({
weapon: { type: Schema.Types.ObjectId, ref: 'Weapon' },
user: { type: Schema.Types.ObjectId, ref: 'User' },
kills: {
type: Number,
required: true,
unique: false,
},
deaths: {
type: Number,
required: true,
unique: false
},
equippedSkin: {
type: Schema.Types.ObjectId, ref: 'WeaponSkin',
required: false,
},
ownedWeaponSkins: [{ type: Schema.Types.ObjectId, ref: 'WeaponSkin'}]
});
const UserSchema = new Schema({
username: {
type: String,
required: true,
unique: true,
},
password: {
type: String,
required: true,
},
weapons: [{
type: Schema.Types.ObjectId, ref: 'UserWeapon'
}],
});
You can use $inc operator and run update operation, something like:
UserWeaponSchema.update({ weapon: weaponId, user: userId }, { '$inc': { 'kills': newAmmountOfKills } })
I have this User model:
const userSchema = new Schema({
_id: {
type: Schema.Types.ObjectId,
required: true
},
name: {
type: String,
required: true
},
email: {
type: String,
unique: true,
required: true
},
notification: {
experiment_id: {
type: Schema.Types.ObjectId,
ref: "Experiment",
required: false
},
seen: {
type: Boolean,
required: true,
default: false
}
}
});
And this Experiment model:
const experimentSchema = new Schema(
{
_id: {
type: Schema.Types.ObjectId,
required: true
},
name: {
type: String,
required: true
},
description: {
type: String,
required: true,
default: "No Description"
},
author_id: {
type: Schema.Types.ObjectId,
ref: "User",
required: true
}
);
I am trying to populate from User the experiment_id in notification.
And from this populate, I would like to populate the author_id as well.
I have seen some code like I have done below but I didn't succeed.
I am trying this:
User.find(
{
_id: req.params.currentUserId
},
"notification"
)
.populate({ path: "experiment_id", populate: { path: "author_id" } })
.exec((err, notif) => {
});
I fixed it by adding notification.experiment_id in the path
User.find(
{
_id: req.params.currentUserId
},
"notification"
)
.populate({ path: "notification.experiment_id", populate: { path: "author_id" } })
.exec((err, notif) => {
});
I have a schema
const RoomSchema = mongoose.Schema({
title: {
type: String,
required: true
},
body: {
type: String,
required: true
},
author: {
type: String,
required: true
},
resource: {
type: String
},
posts: {
type: Array,
default: []
},
url: {
type: String
},
created_at: {
type: String,
required: true
}});
Field 'posts' is another document in my db, defined by the following schema:
const PostSchema = mongoose.Schema({
header: {
type: String,
required: true
},
body: {
type: String,
required: true
},
author: {
username: {type:String, required: true},
_id: {type:String, required:true}
},
room: {
type: String,
required: true
}});
So, I'm trying to create a query that would update fields of certain post inside posts array inside room. I've already tried suggested here, thought without results. I would appreciate any help on the subject
Room.update({ '_id': roomId, 'posts._id': postId },
{ $set: { 'posts.$.header': newHeader, 'posts.$.body': newBody } },
callback);