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How to set _id to db document in Mongoose?
(4 answers)
Closed 5 years ago.
I want to save data to a database with my custom _id,
but I get an error: Cast to ObjectID failed for value...
I think that I shoyld convert my _id and then call the save() method.
Here is my code for this:
var uid = decodedToken.uid;
var body = _.pick(req.body, ['email' , 'fname', "lname", "providerID"]);
body._id = uid;
var userEX = new UserEX(body);
userEX.save().then( (user) => {
res.send(user);
}).catch( (err) => {
res.status(400).send(err);
});
Hope you can help me with that.
Thank you.
Your custom uid is not of type ObjectID.
By default Mongoose _id is of type ObjectID so they don't match.
You could specifically define _id in your schema to be the same type as your custom uid, for example:
var mySchema = new Schema({
_id: String,
// Other fields
});
However, it might be a better idea to leave the default _id as ObjectID and have a secondary uid field which you can use to query, etc.
Related
What is the purpose of using Object Id here?
app.get('/product/:id', async(req, res) => {
const id = req.params.id;
const query = { _id: ObjectId(id) };
const product = await productCollection.findOne(query);
res.send(product);
})
The field name _id is reserved for use as a primary key; its value must be unique in the collection, is immutable, and may be of any type other than an array as default mongo use it as ObjectId.
So the purpose you parse the id it because id its a String and in you database _id it not a string it an ObjectId.
Note: if you are using mongoose you don't need to parse the id to ObjectId cause mongoose auto cast that field to ObjectId
I have already seen the discussion about the following question with a similar title
mongoose 'findById' returns null with valid id
But my problem is not the database name since all my other connections with the same database in fact the queries on the same collection are working fine.
I am using mongoose 4.13.6, node js 6.11 and mongo 3.4.
It is a post request .
var query=req.body;
I am sending the search parameters as
var findFruit =
{
_id:query._id
}
When I print my findFruit I get :
_id:'5a1cf77920701c1f0aafb85e'
The controller function for this is :
Fruit.findById(findFruit._id,function(err,fruit){
if( _.isNull(err) ){
var response = genRes.generateResponse(true,"found successfully");
callback(response);
}
else{
var response = genRes.generateResponse(false,"there occured some error : "+err);
callback(response);
}
})
I even tried find
Fruit.find(findFruit,function(err,fruit){
if( _.isNull(err) ){
var response = genRes.generateResponse(true,"found successfully");
callback(response);
}
else{
var response = genRes.generateResponse(false,"there occured some error : "+err);
callback(response);
}
})
The collection for sure has the entry under this id .
I went through this git issue as well https://github.com/Automattic/mongoose/issues/3079
Unfortunately I cannot downgrade mongoose as it might affect multiple other working functions.
Edit :
I tried creating ObjectId like :
var mongoose = require('mongoose');
var ObjectID = require('mongodb').ObjectID;
var objectId = new ObjectID();
// Convert the object id to a hex string
var originalHex = objectId.toHexString();
// Create a new ObjectID using the createFromHexString function
var newObjectId = new ObjectID.createFromHexString(query._id);
The model file :
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var ObjectId = Schema.ObjectId;
var FruitSchema = new Schema({
name : {type : String, unique : true},
color : {type : String}
});
module.exports = mongoose.model('Fruit', FruitSchema);
All my findById("id") calls returned null.
When looking at the collection with Compass I realized that all my _id elements were Strings. Note that the entire collection was imported.
I created a new element in Compass and the _id was created as ObjectId! and when I called findById("id") with that element's id it worked!
My conclusion is that there is obviously a bug with import. I have not found a way to convert the string _id fields to ObjectId's in the actual collection.
All my findById("id") calls returned null, when _id elements are Strings.
In the first place:
Check your mongodb database, if _id is stored as String, findById(id) can not find since it identifies ObjectId. If you've used import database by using mongoimport command and including _id in JSON:
Solution 1:
modify your JSON and for each document, change _id for instance:
_id: "5a68fde3f09ad7646ddec17e" to the following and run mongoimport again:
"_id": { "$oid": "5a68fde3f09ad7646ddec17e" }
Solution 2:
delete _id in the JSON file, drop collection and import again. Mongo will auto-create _id.
After any of solutions above, findById("id") will work.
Secondly:
Specifically in such cases where your _id elements are string, might be a better idea to use mongodb package: npm i mongodb
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function (err, db) {
if (err) throw err;
var dbo = db.db("your_db_name");
dbo.collection("fruits_collection")
.find({_id:'5a1cf77920701c1f0aafb85e'})
//.find({_id:'5a1cf77920701c1f0aafb85e'}, { projection: { _id: 0, name: 1, color: 1} }) // to select specific columns desired
.toArray(function (err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
The above simple code, assumed you manage error handling yourself, either through try-catch, or
sending 404 as status code, or redirect to error page template, depending on whether the code is embedded in the Express route handler or not.
Hope this helped .. :)
Still trying to figure out why findById didn't work for me but the following piece of code did it
var mongoose = require('mongoose');
var newObjectId=new mongoose.Types.ObjectId(query._id);
var params={
'_id':newObjectId
}
Fruit.find(params).exec(function (err,fruit) {
if( _.isNull(err) ){
var response = genRes.generateResponse(true,"found successfully");
callback(response);
}
else{
var response = genRes.generateResponse(false,"there occured some error : "+err);
callback(response);
}
})
#Shoom. Yes, worked for me, thanks. findById() expects ObjectID, not a String.
I did not have a constraint to create documents with a specific id, so I imported with no _id. The db had newly-assigned _id as ObjectID.
findById(id), (and updateOne({ _id: id }, ...), started working as expected.
Using: node/express/mongodb/mongoose
With the setup listed above, I have created my schema and model and can query as needed. What I'm wondering how to do though is, pass the express request.query object to Model.find() in mongoose to match and query the _id of a nested document. In this instance, the query may look something like:
http://domain.com/api/object._id=57902aeec07ffa2290f179fe
Where object is a nested object that exists elsewhere in the database. I can easily query other fields. _id is the only one giving an issue. It returns an empty array of matches.
Can this be done?
This is an example and not the ACTUAL schema but this gets the point across..
let Category = mongoose.Schema({
name: String
})
let Product = mongoose.Schema({
name: String,
description:String,
category:Category
})
// sample category..
{
_id:ObjectId("1234567890"),
name: 'Sample Category'
}
// sample product
{
_id:ObjectId("0987654321"),
name:'Sample Product',
description:'Sample Product Description',
category: {
_id:ObjectId("1234567890"),
name: 'Sample Category'
}
}
So, what I'm looking for is... if I have the following in express..
app.get('/products',function(req,res,next){
let query = req.query
ProductModel.find(query).exec(function(err,docs){
res.json(docs)
})
})
This would allow me to specify anything I want in the query parameters as a query. So I could..
http://domain.com/api/products?name=String
http://domain.com/api/products?description=String
http://domain.com/api/products?category.name=String
I can query by category.name like this, but I can't do:
http://domain.com/api/products?category._id=1234567890
This returns an empty array
Change your query to http://domain.com/api/object/57902aeec07ffa2290f179fe and try
app.get('/api/object/:_id', function(req, res) {
// req._id is Mongo Document Id
// change MyModel to your model name
MyModel.findOne( {'_id' : req._id }, function(err, doc){
// do smth with this document
console.log(doc);
});
});
or try this one
http://domain.com/api/object?id=57902aeec07ffa2290f179fe
app.get('/api/object', function(req, res) {
var id = req.param('id');
MyModel.findOne( {'_id' : id }, function(err, doc){
console.log(doc);
});
})
First of all increase your skills in getting URL and POST Parameters by this article.
Read official Express 4.x API Documentation
Never mind I feel ridiculous. It works just as I posted above.. after I fixed an error in my schema.
Due to a management decision, we are using userId for the users collection, postId for the posts collection, and topicId for the topics collection, instead of '_id' for each collection as the unique identifier.
This causes a few problems getting started - one of the problems I have encountered is with upserts -
Using Mongoose, we have a schema that restricts userId to be a unique value - but when doing an update on a user model, with upsert set to true, MongoDB appears to only look at the ObjectIds of a collection to see if the same one exists - it doesn't check to see if a model already exists with the same userId - therefore Mongo does an insert instead of an update.
let me illustrate this with some data:
let's say the user's collection has one document:
{
_id:'561b0fad638e99481ab6d84a'
userId:3,
name:'foo'
}
we then run:
User.update({userId:3},{"$set":{name:'bar'},{upsert:true},function(err,resp){
if(err){
// "errMessage": "insertDocument :: caused by :: 11000 E11000 duplicate key error index: app42153482.users.$userId_1 dup key: { : 3 }",
}
});
one would think that MongoDB would find the existing document with userId:3 and udpate it, so there must be something I am doing wrong since it's giving me the duplicate key error?
Typically the default value ObjectId is more ideal for the _id. Here, in this situation you can either override the default _id or you can have your own field for id(like userId in your case).
Use a separate counters collection to track the last number sequence used. The _id field contains the sequence name and the seq field contains the last value of the sequence.
Insert into the counters collection, the initial value for the userid:
db.counters.insert( {
_id: "userid",
seq: 0 } )
Create a getNextSequence function that accepts a name of the sequence. The function uses the findAndModify() method to atomically increment the seq value and return this new value:
function getNextSequence(name) {
var ret = db.counters.findAndModify(
{
query: { _id: name },
update: { $inc: { seq: 1 } },
new: true
}
);
return ret.seq;
}
Use this getNextSequence() function during insert().
db.users.insert(
{
_id: getNextSequence("userid"),
name: "Sarah C."
}
)
db.users.insert(
{
_id: getNextSequence("userid"),
name: "Bob D."
}
)
This way you can maintain as many sequences as you want in the same counter collection. For the upsert issue, check out the Optimistic Loop block in this link Create an auto-increment sequence field.
The second approach is to use a mongoose middleware like mongodb-autoincrement.
Hope it helps.
I don't know which versions of MongoDB and Mongoose you are using, but I couldn't reproduce your problem with MongoDB 3.0 and Mongoose 4.1.10.
I made a sample for you which will create and save a new user, update (using upsert) it, and create another one through an upsert. Try running this code:
"use strict";
var mongoose=require("mongoose");
var Schema = require('mongoose').Schema;
var ObjectId = mongoose.Schema.Types.ObjectId;
// Connect to test
mongoose.connect("mongodb://localhost:27017/test");
// Lets create your schema
var userSchema = new Schema({
_id: ObjectId,
userId: {type: Number, unique: true },
name: String
});
var User = mongoose.model("User", userSchema, "Users");
User.remove() // Let's prune our collection to start clean
.then( function() {
// Create our sample record
var myUser = new User({
_id:'561b0fad638e99481ab6d84a',
userId:3,
name:'foo'
});
return myUser.save();
})
.then( function() {
// Now its time to update (upsert userId 3)
return User.update({userId:3},{"$set":{name:'bar'}},{upsert:true});
})
.then( function() {
// Now its time to insert (upsert userId 4)
return User.update({userId:4},{"$set":{name:'bee'}},{upsert:true});
})
.then( function() {
// Lets show what we have inserted
return User.find().then(function(data) {console.log(data)});
})
.catch( function(err) {
// Show errors if anything goes wrong
console.error("ERROR", err);
})
.then( function() {
mongoose.disconnect();
});
Following the documentation (of MongoDB 3.0) upsert:true will only not insert a non-existing document if your query conditions match on the _id field.
See: https://docs.mongodb.org/manual/reference/method/db.collection.update/#mongodb30-upsert-id
Why are you not using the user_name for a user as unique id?
Because auto-incrementing fields as ids are a bad practice to use in a mongodb environment, especially if you want to use sharding
=> all your inserts will occur on the latest shard
=> the mongodb cluster will have to rebalance often / redistribute the data around.
(Currently this will not occur on your system as you still use the generated _id field)
You can off course also create a unique index on the user_id field:
https://docs.mongodb.org/manual/core/index-unique/#index-type-unique
I am trying to add a couple of attributes to the scaffolded MEAN.js User entity.
locationName: {
type: String,
trim: true
}
I also have created another entity Book connected with User. Unfortunately, I think I do not quite grasp the concept behind the populate method because I am not able to "populate" the User entity with the locationName attribute.
I tried the following:
/**
* List of Books
*/
exports.list = function(req, res) {
Book.find().sort('-created').populate('user', 'displayName', 'locationName').exec(function(err, books) {
if (err) {
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
res.jsonp(books);
}
});
};
Unfortunately, I get the following error:
/home/maurizio/Workspace/sbr-v1/node_modules/mongoose/lib/connection.js:625
throw new MongooseError.MissingSchemaError(name);
^
MissingSchemaError: Schema hasn't been registered for model "locationName".
Any suggestion?
Thanks
Cheers
The error is clear, you should have a schema for the locationName.
If your location is just a string property in your user model and does not refer to separate model, you don't need and shouldn't use populate with it, it will simply be returned as a property of the returned user object from mongoose find() method.
If your want to make your location a stand alone entity (different mongodb document), you should have a mongoose model that defines your location object, aka have a file in your app\models name for example: location.server.model.js that contains something like:
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var LocationSchema = new Schema({
_id: String,
name: String
//, add any additional properties
});
mongoose.model('Location', LocationSchema);
Note that the _id here replaces the auto generated objectId, so this has to be unique, and this the property you should refer to in your User object, meaning if you have a location like this:
var mongoose = require('mongoose'),
Location = mongoose.model('Location');
var _location = new Location({_id:'de', name:'Deutschland'});
you should refer to it in your User object like this:
var _user=new User({location:'de'});
//or:
var _user=new User();
_user.location='de';
then you should be able to populate your location object with your user, like this:
User.find().populate('location').exec(function(err, _user) {
if (err) {
//handle error
} else {
//found user
console.log(_user);
//user is populated with location object, makes you able to do:
console.log(_user.location.name);
}
});
I suggest you to further read in mongodb data modeling and mongoose Schemas, Models, Population.