I have the following three models:
var User = {
first_name: String,
last_name: String,
}
var Student = {
role = String,
user = {type: mongoose.Schema.Types.ObjectId, ref: 'User'}
groups = [{type: mongoose.Schema.Types.ObjectId, ref: 'Group'}],
}
var Group = {
name = String,
students = [{type: mongoose.Schema.Types.ObjectId, ref: 'Student'}],
}
My express get method looks like:
router.route('/')
.get(function(req, res){
Group.find().populate('students').exec(function(err, groups){
res.json(groups);
});
My json object returns the array of student objects a that are populated, but i am only receiving a user._id from within each of the student objects. How can I also get the user object to populate? Any info would be awesome! Thanks
You can populate across multiple levels:
router.route('/')
.get(function(req, res){
Group
.find()
.populate({
path: 'students',
// Get the student's user ids
populate: { path: 'user' }
})
.exec(function(err, groups){
res.json(groups);
});
You can read more about it here
I am currently trying to learn how to work with NoSQL, coming from a relational database background. In this project, I am using Express with Mongoose.
I am struggling with callbacks as I try to merge two models together, which reference each other. I am trying to edit each item in a group of one model (Ribbits) to contain the attributes of another (Users who posted a Ribbit). Because the call to find the User associated with a Ribbit is asynchronous, I am unable to return the collection of edited Ribbits (with user info).
In my website, I have ribbits (a.k.a. tweets) which belong to users. Users can have many ribbits. In one of my pages, I would like to list all of the ribbits on the service, and some information associated with the user who posted that ribbit.
One solution I found was embedded documents, but I discovered that this is, in my case, limited to showing ribbits which belong to a user. In my case, I want to start by getting all of the ribbits first, and then, for each ribbit, attach info about who posted that.
Ideally, I'd want my schema function to return an array of Ribbit objects, so that I can then render this in my view.
// models/user.js
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var userSchema = Schema({
username: String,
email: String,
password: String,
name: String,
profile: String,
ribbits: [{
type: Schema.Types.ObjectId,
ref: 'Ribbit',
}]
});
module.exports = mongoose.model('User', userSchema);
// models/ribbit.js
var mongoose = require('mongoose'),
Schema = mongoose.Schema,
User = require('./user');
var ribbitSchema = Schema({
content: { type: String, maxlength: 140 },
created: { type: Date, default: Date.now() },
owner: { type: Schema.Types.ObjectId, ref: 'User' },
});
ribbitSchema.methods.getOwnerObj = function(cb) {
return User.findOne({ _id: this.owner }, cb);
}
ribbitSchema.statics.getAllRibbits = function(cb) {
this.find({}, function(err, ribbits) {
console.log('Before Transform');
console.log(ribbits);
ribbits.forEach(function(ribbit) {
ribbit.getOwnerObj(function(err, owner) {
ribbit = {
content: ribbit.content,
created: ribbit.created,
owner: {
username: owner.username,
email: owner.email,
name: owner.name,
profile: owner.profile,
}
};
});
});
});
}
module.exports = mongoose.model('Ribbit', ribbitSchema);
If I understand correctly, you can use Mongoose populate method for this scenario:
ribbitSchema.statics.getAllRibbits = function(cb) {
this.find({}).populate('owner').exec(function(err, ribbits){
console.log(ribbits[0].owner)
return cb(err, ribbits);
})
}
According to this mongodb article it is possible to auto increment a field and I would like the use the counters collection way.
The problem with that example is that I don't have thousands of people typing the data in the database using the mongo console. Instead I am trying to use mongoose.
So my schema looks something like this:
var entitySchema = mongoose.Schema({
testvalue:{type:String,default:function getNextSequence() {
console.log('what is this:',mongoose);//this is mongoose
var ret = db.counters.findAndModify({
query: { _id:'entityId' },
update: { $inc: { seq: 1 } },
new: true
}
);
return ret.seq;
}
}
});
I have created the counters collection in the same database and added a page with the _id of 'entityId'. From here I am not sure how to use mongoose to update that page and get the incrementing number.
There is no schema for counters and I would like it to stay that way because this is not really an entity used by the application. It should only be used in the schema(s) to auto increment fields.
Here is an example how you can implement auto-increment field in Mongoose:
var CounterSchema = Schema({
_id: {type: String, required: true},
seq: { type: Number, default: 0 }
});
var counter = mongoose.model('counter', CounterSchema);
var entitySchema = mongoose.Schema({
testvalue: {type: String}
});
entitySchema.pre('save', function(next) {
var doc = this;
counter.findByIdAndUpdate({_id: 'entityId'}, {$inc: { seq: 1} }, function(error, counter) {
if(error)
return next(error);
doc.testvalue = counter.seq;
next();
});
});
You can use mongoose-auto-increment package as follows:
var mongoose = require('mongoose');
var autoIncrement = require('mongoose-auto-increment');
/* connect to your database here */
/* define your CounterSchema here */
autoIncrement.initialize(mongoose.connection);
CounterSchema.plugin(autoIncrement.plugin, 'Counter');
var Counter = mongoose.model('Counter', CounterSchema);
You only need to initialize the autoIncrement once.
The most voted answer doesn't work. This is the fix:
var CounterSchema = new mongoose.Schema({
_id: {type: String, required: true},
seq: { type: Number, default: 0 }
});
var counter = mongoose.model('counter', CounterSchema);
var entitySchema = mongoose.Schema({
sort: {type: String}
});
entitySchema.pre('save', function(next) {
var doc = this;
counter.findByIdAndUpdateAsync({_id: 'entityId'}, {$inc: { seq: 1} }, {new: true, upsert: true}).then(function(count) {
console.log("...count: "+JSON.stringify(count));
doc.sort = count.seq;
next();
})
.catch(function(error) {
console.error("counter error-> : "+error);
throw error;
});
});
The options parameters gives you the result of the update and it creates a new document if it doesn't exist.
You can check here the official doc.
And if you need a sorted index check this doc
So combining multiple answers, this is what I ended up using:
counterModel.js
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
const counterSchema = new Schema(
{
_id: {type: String, required: true},
seq: { type: Number, default: 0 }
}
);
counterSchema.index({ _id: 1, seq: 1 }, { unique: true })
const counterModel = mongoose.model('counter', counterSchema);
const autoIncrementModelID = function (modelName, doc, next) {
counterModel.findByIdAndUpdate( // ** Method call begins **
modelName, // The ID to find for in counters model
{ $inc: { seq: 1 } }, // The update
{ new: true, upsert: true }, // The options
function(error, counter) { // The callback
if(error) return next(error);
doc.id = counter.seq;
next();
}
); // ** Method call ends **
}
module.exports = autoIncrementModelID;
myModel.js
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
const autoIncrementModelID = require('./counterModel');
const myModel = new Schema({
id: { type: Number, unique: true, min: 1 },
createdAt: { type: Date, default: Date.now },
updatedAt: { type: Date },
someOtherField: { type: String }
});
myModel.pre('save', function (next) {
if (!this.isNew) {
next();
return;
}
autoIncrementModelID('activities', this, next);
});
module.exports = mongoose.model('myModel', myModel);
Attention!
As hammerbot and dan-dascalescu pointed out this does not work if you remove documents.
If you insert 3 documents with id 1, 2 and 3 - you remove 2 and insert another a new one it'll get 3 as id which is already used!
In case you don't ever remove documents, here you go:
I know this has already a lot of answers, but I would share my solution which is IMO short and easy understandable:
// Use pre middleware
entitySchema.pre('save', function (next) {
// Only increment when the document is new
if (this.isNew) {
entityModel.count().then(res => {
this._id = res; // Increment count
next();
});
} else {
next();
}
});
Make sure that entitySchema._id has type:Number.
Mongoose version: 5.0.1.
This problem is sufficiently complicated and there are enough pitfalls that it's best to rely on a tested mongoose plugin.
Out of the plethora of "autoincrement" plugins at http://plugins.mongoosejs.io/, the best maintained and documented (and not a fork) is mongoose sequence.
I've combined all the (subjectively and objectively) good parts of the answers, and came up with this code:
const counterSchema = new mongoose.Schema({
_id: {
type: String,
required: true,
},
seq: {
type: Number,
default: 0,
},
});
// Add a static "increment" method to the Model
// It will recieve the collection name for which to increment and return the counter value
counterSchema.static('increment', async function(counterName) {
const count = await this.findByIdAndUpdate(
counterName,
{$inc: {seq: 1}},
// new: return the new value
// upsert: create document if it doesn't exist
{new: true, upsert: true}
);
return count.seq;
});
const CounterModel = mongoose.model('Counter', counterSchema);
entitySchema.pre('save', async function() {
// Don't increment if this is NOT a newly created document
if(!this.isNew) return;
const testvalue = await CounterModel.increment('entity');
this.testvalue = testvalue;
});
One of the benefits of this approach is that all the counter related logic is separate. You can store it in a separate file and use it for multiple models importing the CounterModel.
If you are going to increment the _id field, you should add its definition in your schema:
const entitySchema = new mongoose.Schema({
_id: {
type: Number,
alias: 'id',
required: true,
},
<...>
});
test.pre("save",function(next){
if(this.isNew){
this.constructor.find({}).then((result) => {
console.log(result)
this.id = result.length + 1;
next();
});
}
})
I didn't wan to use any plugin (an extra dependencie, initializing the mongodb connection apart from the one I use in the server.js, etc...) so I did an extra module, I can use it at any schema and even, I'm considering when you remove a document from the DB.
module.exports = async function(model, data, next) {
// Only applies to new documents, so updating with model.save() method won't update id
// We search for the biggest id into the documents (will search in the model, not whole db
// We limit the search to one result, in descendant order.
if(data.isNew) {
let total = await model.find().sort({id: -1}).limit(1);
data.id = total.length === 0 ? 1 : Number(total[0].id) + 1;
next();
};
};
And how to use it:
const autoincremental = require('../modules/auto-incremental');
Work.pre('save', function(next) {
autoincremental(model, this, next);
// Arguments:
// model: The model const here below
// this: The schema, the body of the document you wan to save
// next: next fn to continue
});
const model = mongoose.model('Work', Work);
module.exports = model;
Hope it helps you.
(If this Is wrong, please, tell me. I've been having no issues with this, but, not an expert)
Here is a proposal.
Create a separate collection to holds the max value for a model collection
const autoIncrementSchema = new Schema({
name: String,
seq: { type: Number, default: 0 }
});
const AutoIncrement = mongoose.model('AutoIncrement', autoIncrementSchema);
Now for each needed schema, add a pre-save hook.
For example, let the collection name is Test
schema.pre('save', function preSave(next) {
const doc = this;
if (doc.isNew) {
const nextSeq = AutoIncrement.findOneAndUpdate(
{ name: 'Test' },
{ $inc: { seq: 1 } },
{ new: true, upsert: true }
);
nextSeq
.then(nextValue => doc[autoIncrementableField] = nextValue)
.then(next);
}
else next();
}
As findOneAndUpdate is an atomic operation, no two updates will return same seq value. Thus each of your insertion will get an incremental seq regardless of number of concurrent insertions. Also this can be extended to more complex auto incremental logic and the auto increment sequence is not limited to Number type
This is not a tested code. Test before you use until I make a plugin for mongoose.
Update I found that this plugin implemented related approach.
The answers seem to increment the sequence even if the document already has an _id field (sort, whatever). This would be the case if you 'save' to update an existing document. No?
If I'm right, you'd want to call next() if this._id !== 0
The mongoose docs aren't super clear about this. If it is doing an update type query internally, then pre('save' may not be called.
CLARIFICATION
It appears the 'save' pre method is indeed called on updates.
I don't think you want to increment your sequence needlessly. It costs you a query and wastes the sequence number.
I had an issue using Mongoose Document when assigning value to Schema's field through put(). The count returns an Object itself and I have to access it's property.
I played at #Tigran's answer and here's my output:
// My goal is to auto increment the internalId field
export interface EntityDocument extends mongoose.Document {
internalId: number
}
entitySchema.pre<EntityDocument>('save', async function() {
if(!this.isNew) return;
const count = await counter.findByIdAndUpdate(
{_id: 'entityId'},
{$inc: {seq: 1}},
{new: true, upsert: true}
);
// Since count is returning an array
// I used get() to access its child
this.internalId = Number(count.get('seq'))
});
Version: mongoose#5.11.10
None of above answer works when you have unique fields in your schema
because unique check at db level and increment happen before db level validation, so you may skip lots of numbers in auto increments like above solutions
only in post save can find if data already saved on db or return error
schmea.post('save', function(error, doc, next) {
if (error.name === 'MongoError' && error.code === 11000) {
next(new Error('email must be unique'));
} else {
next(error);
}
});
https://stackoverflow.com/a/41479297/10038067
that is why none of above answers are not like atomic operations auto increment in sql like dbs
I use together #cluny85 and #edtech.
But I don't complete finish this issues.
counterModel.findByIdAndUpdate({_id: 'aid'}, {$inc: { seq: 1} }, function(error,counter){
But in function "pre('save...) then response of update counter finish after save document.
So I don't update counter to document.
Please check again all answer.Thank you.
Sorry. I can't add comment. Because I am newbie.
var CounterSchema = Schema({
_id: { type: String, required: true },
seq: { type: Number, default: 0 }
});
var counter = mongoose.model('counter', CounterSchema);
var entitySchema = mongoose.Schema({
testvalue: { type: String }
});
entitySchema.pre('save', function(next) {
if (this.isNew) {
var doc = this;
counter.findByIdAndUpdate({ _id: 'entityId' }, { $inc: { seq: 1 } }, { new: true, upsert: true })
.then(function(count) {
doc.testvalue = count.seq;
next();
})
.catch(function(error) {
throw error;
});
} else {
next();
}
});
I got a weird behavior with mongoose, it seems that closing the db connection after saving my schema erases it.
Here's my schema brand.js:
var brandSchema = new db.Schema({
id: {type: String, required: true, index: {unique: true}},
products: [String]
});
I execute the following script to populate my database (important precision: before executing the script, my brand table is not defined in the DB):
var async = require('async');
//Get config
var middlewares = require('./middlewares');
var config = require('./config');
//Load model
require('./models/brand');
var db = middlewares.db(config);
// Load brand.json
var brands = require('./brands.json');
// Save each brand in the database
async.each(Object.keys(brands), function(brandId, callback){
var brand = new Brand({id: brandId, products: brands[brandsId]);
brand.save(function(err){
if(err) console.log(err);
else console.log('brand ' + brand.id + ' added');
callback();
});
}, function(){
//Properly close the connection so the script can terminate
db.connection.close();
});
This script gives the following logs:
Mongoose: brand.ensureIndex({ id: 1 }) { safe: undefined, background: true, uni
que: true }
Mongoose: brand.insert({ __v: 0, products: [ 'phone', 'tv'], _id: ObjectId(
"54524f612245da0c2f0d2ba7"), id: 'samsung' }) {}
Mongoose: brand.insert({ __v: 0, products: [ 'food', 'beverages' ], _id: ObjectId(
"54524f612245da0c2f0d2ba8"), id: '' }) {}
The first line of the logs suggests that an index id is created with the right parameters. But when I look into the DB, my brands are saved but the brand schema is empty. However, if I remove db.connection.close(), brands are still saved and the schema is saved like defined in Brand.
I don't really understand why. Could it be because of buffered data not sent to the db ?
I am beginner in Express. I have the following code in my router/controller for update a model. In one hand I don't want to modify the date of "create_date" parameter, and on the second hand this code returns me a error.
updateFood = function(req, res){
Food.findById(req.params.id, function(err, food){
food.food_name = req.body.food_name;
food.description = req.body.description;
food.image = req.body.image;
food.create_date = Date.now();
food.category = req.body.category;
Food.save(function(err){
if (!err){
console.log("updated!");
} else {
console.log(err);
}
});
res.send(food);
});
};
Here is my schema:
var food = new Schema({
food_name: {type: String, unique: true},
description: String,
image: String,
create_date: {type: Date, default: Date.now()},
category: {
type: String,
cats: ['Meat', 'Fish', 'Vegetables']
}
});
module.exports = mongoose.model('Food', food);
When I try to update a food with Postman with PUT. The console returns me the following response:
Food.save(function(err){
^
TypeError: Object function model(doc, fields, skipId) {
if (!(this instanceof model))
return new model(doc, fields, skipId);
Model.call(this, doc, fields, skipId);
} has no method 'save'
What can I do? Anyone knows where is my mistake? Thanks.
I believe you meant food.save(..); instead of Food.save(..);, but if all you're doing is updating the model, you could use findByIdAndUpdate() instead.