This question already has answers here:
Mongoose always returning an empty array NodeJS
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Closed 5 years ago.
i am working upon mongoose to list all the data from a collection in a db in mongodb:
from the requests:
http://localhost:3000/listdoc?model=Organization
i am doing the following code :
exports.listDoc = function(req, res) {
var Model = mongoose.model(req.query.model); //This is defined and returns my desired model name
Model.find().populate('name').exec(function(err, models) {
if (err) {
res.render('error', {
status: 500
});
} else {
res.jsonp(models);
}
});
};
I already have my entry in database
But the above code returns empty. Why?
EDIT : the following code also returns empty:
exports.listDoc = function(req, res) {
var Model = mongoose.model(req.query.model);
Model.find({},function(err,models){
console.log(models);
if (err) {
res.render('error', {
status: 500
});
} else {
res.jsonp(models);
}
});
};
schema used :
var Organization = mongoose.Schema({
name: String
});
Your problem is mongoose pluralizes collections. Mongoose is querying "organizations" but your data is in mongodb as "organization". Make them match and you should be good to go. You can either rename it in mongodb via the mongo shell or tell mongoose about it. From the mongoose docs:
var schema = new Schema({ name: String }, { collection: 'actor' });
// or
schema.set('collection', 'actor');
// or
var collectionName = 'actor'
var M = mongoose.model('Actor', schema, collectionName)
From official doc
Population is the process of automatically replacing the specified
paths in the document with document(s) from other collection(s).
Try it without populate
Model.find({}).exec(function(err, models) {
if (err) {
res.render('error', {
status: 500
});
} else {
res.json(models);
}
});
Related
I am having trouble with a simple findById with mongoose.
Confirmed the item exists in the DB
db.getCollection('stories').find({_id:'572f16439c0d3ffe0bc084a4'})
With mongoose
Story.findById(topic.storyId, function(err, res) {
logger.info("res", res);
assert.isNotNull(res);
});
won't find it.
I also tried converting to a mongoId, still cannot be found (even though mongoose supposedly does this for you)
var mid = mongoose.Types.ObjectId(storyId);
let story = await Story.findOne({_id: mid}).exec();
I'm actually trying to use this with typescript, hence the await.
I also tried the Story.findById(id) method, still cannot be found.
Is there some gotcha to just finding items by a plain _id field?
does the _id have to be in the Schema? (docs say no)
I can find by other values in the Schema, just _id can't be used...
update: I wrote a short test for this.
describe("StoryConvert", function() {
it("should read a list of topics", async function test() {
let topics = await Topic.find({});
for (let i = 0; i < topics.length; i ++) {
let topic = topics[i];
// topics.forEach( async function(topic) {
let storyId = topic.storyId;
let mid = mongoose.Types.ObjectId(storyId);
let story = await Story.findOne({_id: mid});
// let story = await Story.findById(topic.storyId).exec();
// assert.equal(topic.storyId, story._id);
logger.info("storyId", storyId);
logger.info("mid", mid);
logger.info("story", story);
Story.findOne({_id: storyId}, function(err, res) {
if (err) {
logger.error(err);
} else {
logger.info("no error");
}
logger.info("res1", res);
});
Story.findOne({_id: mid}, function(err, res) {
logger.info("res2", res);
});
Story.findById(mid, function(err, res) {
logger.info("res3", res);
// assert.isNotNull(res);
});
}
});
});
It will return stuff like
Testing storyId 572f16439c0d3ffe0bc084a4
Testing mid 572f16439c0d3ffe0bc084a4
Testing story null
Testing no error
Testing res1 null
Testing res2 null
Testing res3 null
I noticed that topic.storyId is a string
not sure if that would cause any issues mapping to the other table.
I tried also adding some type defs
storyId: {
type: mongoose.Schema.Types.ObjectId,
required: false
}
Because this query finds the doc in the shell:
db.getCollection('stories').find({_id:'572f16439c0d3ffe0bc084a4'})
That means that the type of _id in the document is actually a string, not an ObjectId like Mongoose is expecting.
To find that doc using Mongoose, you'd have to define _id in the schema for Story as:
_id: { type: String }
If your Mongo schema is configured to use Object Id, you query in nodeJS using
models.Foo.findById(id)
where Foo is your model and id is your id.
here's a working example
router.get('/:id', function(req, res, next) {
var id = req.params.id
models.Foo.findById(id)
.lean().exec(function (err, results) {
if (err) return console.error(err)
try {
console.log(results)
} catch (error) {
console.log("errror getting results")
console.log(error)
}
})
})
In Mongo DB your query would be
{_id:ObjectId('5c09fb04ff03a672a26fb23a')}
One solution is to use mongoose.ObjectId()
const Model = require('./model')
const mongoose = require('mongoose')
Model.find({ id: mongoose.ObjectId(userID) })
It works, but it is weird because we are using id instead of _id
This is how we do it now:
const { mongoose } = require("mongoose");
YourModel.find({ _id: mongoose.Types.ObjectId("572f16439c0d3ffe0bc084a4") });
I got into this scenario too. This was how I solved it;
According to the mongoose documentation, you need to tell mongoose to
return the raw js objects, not mongoose documents by passing the lean option and setting it to true. e.g
Adventure.findById(id, 'name', { lean: true }, function (err, doc) {});
in your situation, it would be
Story.findById(topic.storyId, { lean: true }, function(err, res) {
logger.info("res", res);
assert.isNotNull(res);
});
If _id is the default mongodb key, in your model set the type of _id as this:
_id: mongoose.SchemaTypes.ObjectId
Then usind mongoose you can use a normal find:
YourModel.find({"_id": "5f9a86b77676e180c3089c3d"});
models.findById(id)
TRY THIS ONE .
REF LINK : https://www.geeksforgeeks.org/mongoose-findbyid-function/
Try this
Story.findOne({_id:"572b19509dac77951ab91a0b"}, function(err, story){
if (err){
console.log("errr",err);
//return done(err, null);
}else{
console.log(story);
}
});
I am creating app using nodejs, express, mongoose. And mongodb.user is the mongoose schema model and I am trying to fetch user array of objects, that query is perfect and my problem is I want to add new property for each user. I have tried as follows. But it does not add to the collection.
exports.memberlist = function(req, res) {
user.find({}).exec(function(err, collection) {
collection.forEach(function(member){
member.city = 'Colombo';
collection.push(member);
});
res.send(collection);
});
};
you can do like this
in Schema level create create virtual property
userSchema.virtual('city').get(function () {
return 'Colombo';
});
in controller level
exports.memberlist = function(req, res,next)
{
user.find({}).exec(function(err, users)
{
if(!err)
{
res.json(200, users.toObject({virtual: true}));
}
else
{
next(err);
}
});
};
By default, Mongoose doesn't allow to add a property to an object extracted from MongoDB DB. To do so, you have two alternatives :
1/ before exec statement you add a lean() method :
user.find({}).lean().exec(function(err, collection) {do whatever you want with collection}
2/ collection = collection.toObject();
I have such a problem with Mongoose:
Object in MongoDB
{
_id:1928319237192387,
componists:
{
name:'George Enescu'
}
}
Mongoose Query
var find = function(req, res, next) {
return IP.findById(req.params.id, function(err, artist) {
if(!artist) {
res.status(404).send({
status: 'Not Found'
});
} else if (!err) {
console.log(JSON.stringify(artist.componists.name));
}
}
Output:
undefined
Expected Output:
George Enescu
However logging artist.componists works, giving back {name:'George Enescu'}
Found the error already. I had to make sure to define the correct type in the artist Schema.
var ArtistSchema = mongoose.Schema({
componists: {type:String}
});
I originally had set the type to type:Number returning undefined.
Virtual + Schemaless = Bug?
However, I also noticed that if I have the schema defined as Mixed {}, that virtuals won't work.
I have a function that is needed to get results.
When I give 1 as _id filter everything is OK.
collectionPersonnel
.find({ '_id' : 1 })
.toArray(function (err, personnel) {
console.log(personnel);
});
If I give filter another way for instance user[0]['personnel_id'] -that is store 1- then I get only [] result;
collectionPersonnel
.find({ '_id' : user[0]['personnel_id'] })
.toArray(function (err, personnel) {
console.log(personnel);
});
And then I've tried another way. But it doesn't work because I used a string(user[0]['personnel_id']) instead of an ObjectID.
var ObjectID = require('mongodb').ObjectID;
var personnelPK_Hex = (user[0]['personnel_id']).toHexString();
var personnelPK = ObjectID.createFromHexString(personnelPK_Hex);
What should I do?
Edit
All of my codes are below;
module.exports = {
show: function(req, res) {
User.native(function(err, collectionUser) {
if(err) {
console.log("There is no exist a User by current_id");
};
collectionUser
.find({'_id' : req.param('id')})
.toArray(function (err, user) {
Personnel.native(function(err, collectionPersonnel) {
if(err) {
// handle error getting mongo collection
console.log("There is no exist a Personel by current _id");
};
if(!collectionPersonnel) {
console.log("There is no exist a Personel by current _id");
};
// var ObjectID = require('mongodb').ObjectID;
// var personnelPK_Hex = (user[0]['personnel_id']).toHexString();
// var personnelPK = ObjectID.createFromHexString(personnelPK_Hex);
collectionPersonnel
.find({ '_id' : user[0].personnel_id })
.toArray(function (err, personnel) {
console.log(personnel);
});
});
});
});
}
};
And console's output is;
[]
Solved
Just like apsillers's said. I had given a numeric _id to collection, incorrectly.
I've fixed _id value and everything is OK.
Thank you all...
user[0]['personnel_id'] might be a string. For Mongo, "1" is different from 1, which is why your literal number 1 worked, but your variable (which holds a string) does not.
Instead, try using a unary plus to convert the string to a number: +user[0]['personnel_id'].
try to use like user[0].personal_id instead of user[0]['personnel_id'] please provide your schema design that would be better to figure out what exactly you are missing.
i tried like this
collectionPersonnel
.find({ '_id' : user[0].personnel_id })
.toArray(function (err, personnel) {
console.log(personnel);
});
I have a collection "companies" with several objects. Every object has "_id" parameter. I'm trying to get this parameter from db:
app.get('/companies/:id',function(req,res){
db.collection("companies",function(err,collection){
console.log(req.params.id);
collection.findOne({_id: req.params.id},function(err, doc) {
if (doc){
console.log(doc._id);
} else {
console.log('no data for this company');
}
});
});
});
So, I request companies/4fcfd7f246e1464d05000001 (4fcfd7f246e1464d05000001 is _id-parma of a object I need) and findOne returns nothing, that' why console.log('no data for this company'); executes.
I'm absolutely sure that I have an object with _id="4fcfd7f246e1464d05000001". What I'm doing wrong? Thanks!
However, I've just noticed that id is not a typical string field. That's what mViewer shows:
"_id": {
"$oid": "4fcfd7f246e1464d05000001"
},
Seems to be strange a bit...
You need to construct the ObjectID and not pass it in as a string. Something like this should work:
var BSON = require('mongodb').BSONPure;
var obj_id = BSON.ObjectID.createFromHexString("4fcfd7f246e1464d05000001");
Then, try using that in your find/findOne.
Edit: As pointed out by Ohad in the comments (thanks Ohad!), you can also use:
new require('mongodb').ObjectID(req.params.id)
Instead of createFromHexString as outlined above.
That's because _id field in mongo isn't of string type (as your req.params.id). As suggested in other answers, you should explicitly convert it.
Try mongoskin, you could use it like node-mongodb-native driver, but with some sugar. For example:
// connect easier
var db = require('mongoskin').mongo.db('localhost:27017/testdb?auto_reconnect');
// collections
var companies = db.collection('companies');
// create object IDs
var oid = db.companies.id(req.params.id);
// some nice functions…
companies.findById();
//… and bindings
db.bind('companies', {
top10: function(callback) {
this.find({}, {limit: 10, sort: [['rating', -1]]).toArray(callback);
}
});
db.companies.top10(printTop10);
You can use findById() which will take care of the id conversion for you.
company = Company.findById(req.params.id, function(err, company) {
//////////
});
In case these didn't work for you, this worked for me for accessing a blog post:
const getSinglePost = async (req, res) => {
let id = req.params.id;
var ObjectId = require('mongodb').ObjectId;
const db = await client.db('CMS');
const data = await db.collection("posts").findOne({ _id: ObjectId(id) })
if (data) {
res.status(200).send(data)
} else res.status(400).send({ message: "no post found" })
}