I am working on trying to connect a Node/Express server to an existing MongoDB Database/Collection. I have already successfully connected to the database. However, I am having a tremendously difficult time setting up my models/schema to query.
The MongoDB is MongoDB Atlas and has one collection with over 800,000 documents. The name of the single collection is "delitosCollection".
I have tried the following to with no success:
var CrimeData = mongoose.model('DelitosCollection', new Schema({}),'delitosCollection');
mongoose.connection.on('open', function(ref){
console.log("connected to the mongo server");
CrimeData.find({}, (err,results) => {
if(err){
console.log("ERROR")
throw err
}
console.log("results: ", results.length)
} )
});
I know the connection is working as I am receiving the console.log with no errors. However, results.length is returning 0 when it should be over 800,000. Have spent way too many hours on this.
Create an empty schema for each collection you want to use
and then create a model to be used in your project
the model take 3 parameter
1)name of the model
2)schema name
3)collection name ( from mongodb atlas)
like that
const mongoose = require('mongoose');
mongoose.connect('mongodb uri')
const userSchema = new mongoose.Schema({});
const User = mongoose.model('User', userSchema, 'user');
then you can use the model normally
User.find({})
connection to mongo db
// Connect to mongoDB
mongoose.connect('mongodb://localhost/[yourDbName]',{useNewUrlParser:true})
.then(function(){
console.log('mongoDB connected');
})
.catch(function(){
console.log('Error :');
})
after that you will have to create your schema and then only you can query the database
create your schema like this
// Crimes Schema
const CrimeDetailsSchema= new Schema({
first_name: {
type: String,
required: true
},
last_name: {
type: String,
required: true
},
email: {
type: String,
required: true
}
});
const Profile = module.exports = mongoose.model('delitosCollection', CrimeDetailsSchema, 'delitosCollection');
after that create your queries
you can get an idea about that in mongoose documentation here
You can refer to the answer given below, just pass an empty object in schema
like db.model('users', new Schema({}))
i have created model for the mongo collection like below. but it was giving me the collection output which saved in mongoDB.
var mongoose = require('mongoose'),
Schema = mongoose.Schema({
name: {
type: String
},
age: {
type: Number
},
})
module.exports = mongoose.model('container', Schema);}
But later when i changed the last line of the code which is
"module.exports = mongoose.model('container', Schema);"
to
"module.exports = mongoose.model('container', Schema, 'container');"
it worked properly. I check the mongoose document they say to use the previous line, then why didn't it worked.
your problem seems to be from using "Schema" as a variable name
var ContainerSchema = new mongoose.Schema({
...
});
and exporting
module.exports = mongoose.model("Container", ContainerSchema);
would work.
I just started learning MongoDB and mongoose. Currently I have the following structure:
database -> skeletonDatabase
collection -> adminLogin
When I run db.adminLogin.find() from the command line I get:
{ "_id" : ObjectId("52lhafkjasfadsfea"), "username" : "xxxx", "password" : "xxxx" }
My connection (this works, just adding it FYI)
module.exports = function(mongoose)
{
mongoose.connect('mongodb://localhost/skeletonDatabase');
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function callback () {
console.log('Conntected To Mongo Database');
});
}
My -js-
module.exports = function(mongoose)
{
var Schema = mongoose.Schema;
// login schema
var adminLogin = new Schema({
username: String,
password: String
});
var adminLoginModel = mongoose.model('adminLogin', adminLogin);
var adminLogin = mongoose.model("adminLogin");
adminLogin.find({}, function(err, data){
console.log(">>>> " + data );
});
}
My console.log() returns as >>>>
So what am I doing wrong here? Why do I not get any data in my console log? Thanks in advance for any help.
mongoose by default takes singular model names and pairs them with a collection named with the plural of that, so mongoose is looking in the db for a collection called "adminLogins" which doesn't exist. You can specify your collection name as the 2nd argument when defining your schema:
var adminLogin = new Schema({
username: String,
password: String
}, {collection: 'adminLogin'});
Had a problem with injecting it within an express route for my api so I changed it thanks to #elkhrz by first defining the schema and then compiling that one model I want to then pull like so:
app.get('/lists/stored-api', (req, res) => {
Apis.find(function(err, apis) {
if (err) return console.error(err);
res.send(apis);
});
});
I wouldn't send it to the body, I would actually do something else with it especially if you plan on making your API a production based application.
Run through this problem and read up on possible proper ways of rendering your data:
How to Pass Data Between Routes in Express
Always a good idea to practice safe procedures when handling data.
first compile just one model with the schema as an argument
var adminLogin = mongoose.model('adminLogin', adminLogin);
in your code adminLogin does not exist, adminLoginModel does;
after that ,instead to
adminLogin.find({}, function(err, data){
console.log(">>>> " + data );
});
try this
adminLogin.find(function (err, adminLogins) {
if (err) return console.error(err);
console.log(adminLogins);
is important the "s" because mongo use the plural of the model to name the collection, sorry for my english...
I am new to Mongoose. I am struck to get data in every collection in Database.
I have some collections with a field country.
Lets say company_Information is collection having country as a field.
var companyInformation = new Schema({
....
country:{type: String},
..
})
mongoose.model('company_Information',companyInformation);
similarly country field may present in some other collection.
Instead of searching a value of country in each collection using
company_Information.find({ 'country': 'India' })
someCollection.find({ 'country': 'India' })
someCollection2.find({ 'country': 'India' })
is there any way to search a record in every collection in database?
Working example would help me.
Thank you.
For example you can use something like this:
const mongoose = require('mongoose');
const findAllCountries = (country_name)=>{
let models = [];
models.push(mongoose.models.someCollection1);
...
models.push(mongoose.models.someCollectionN);
return Promise.all(models.map(model=>model.find({'country': country_name})));
}
So you can use this function like this:
findAllCountries('USA').then(result=>{
console.log(result);
}).catch(err=>{throw err;})
I have a large collection of 300 question objects in a database test. I can interact with this collection easily through MongoDB's interactive shell; however, when I try to get the collection through Mongoose in an express.js application I get an empty array.
My question is, how can I access this already existing dataset instead of recreating it in express? Here's some code:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
mongoose.connect('mongodb://localhost/test');
mongoose.model('question', new Schema({ url: String, text: String, id: Number }));
var questions = mongoose.model('question');
questions.find({}, function(err, data) { console.log(err, data, data.length); });
This outputs:
null [] 0
Mongoose added the ability to specify the collection name under the schema, or as the third argument when declaring the model. Otherwise it will use the pluralized version given by the name you map to the model.
Try something like the following, either schema-mapped:
new Schema({ url: String, text: String, id: Number},
{ collection : 'question' }); // collection name
or model mapped:
mongoose.model('Question',
new Schema({ url: String, text: String, id: Number}),
'question'); // collection name
Here's an abstraction of Will Nathan's answer if anyone just wants an easy copy-paste add-in function:
function find (name, query, cb) {
mongoose.connection.db.collection(name, function (err, collection) {
collection.find(query).toArray(cb);
});
}
simply do find(collection_name, query, callback); to be given the result.
for example, if I have a document { a : 1 } in a collection 'foo' and I want to list its properties, I do this:
find('foo', {a : 1}, function (err, docs) {
console.dir(docs);
});
//output: [ { _id: 4e22118fb83406f66a159da5, a: 1 } ]
You can do something like this, than you you'll access the native mongodb functions inside mongoose:
var mongoose = require("mongoose");
mongoose.connect('mongodb://localhost/local');
var connection = mongoose.connection;
connection.on('error', console.error.bind(console, 'connection error:'));
connection.once('open', function () {
connection.db.collection("YourCollectionName", function(err, collection){
collection.find({}).toArray(function(err, data){
console.log(data); // it will print your collection data
})
});
});
Update 2022
If you get an MongoInvalidArgumentError: The callback form of this helper has been removed. error message, here's the new syntax using async/await:
const mongoose = require("mongoose");
mongoose.connect('mongodb://localhost/productsDB');
const connection = mongoose.connection;
connection.on('error', console.error.bind(console, 'connection error:'));
connection.once('open', async function () {
const collection = connection.db.collection("Products");
collection.find({}).toArray(function(err, data){
console.log(data); // it will print your collection data
});
});
I had the same problem and was able to run a schema-less query using an existing Mongoose connection with the code below. I've added a simple constraint 'a=b' to show where you would add such a constraint:
var action = function (err, collection) {
// Locate all the entries using find
collection.find({'a':'b'}).toArray(function(err, results) {
/* whatever you want to do with the results in node such as the following
res.render('home', {
'title': 'MyTitle',
'data': results
});
*/
});
};
mongoose.connection.db.collection('question', action);
Are you sure you've connected to the db? (I ask because I don't see a port specified)
try:
mongoose.connection.on("open", function(){
console.log("mongodb is connected!!");
});
Also, you can do a "show collections" in mongo shell to see the collections within your db - maybe try adding a record via mongoose and see where it ends up?
From the look of your connection string, you should see the record in the "test" db.
Hope it helps!
Something else that was not obvious, to me at least, was that the when using Mongoose's third parameter to avoid replacing the actual collection with a new one with the same name, the new Schema(...) is actually only a placeholder, and doesn't interfere with the exisitng schema so
var User = mongoose.model('User', new Schema({ url: String, text: String, id: Number}, { collection : 'users' })); // collection name;
User.find({}, function(err, data) { console.log(err, data, data.length);});
works fine and returns all fields - even if the actual (remote) Schema contains none of these fields. Mongoose will still want it as new Schema(...), and a variable almost certainly won't hack it.
Go to MongoDB website, Login > Connect > Connect Application > Copy > Paste in 'database_url' > Collections > Copy/Paste in 'collection' .
var mongoose = require("mongoose");
mongoose.connect(' database_url ');
var conn = mongoose.connection;
conn.on('error', console.error.bind(console, 'connection error:'));
conn.once('open', function () {
conn.db.collection(" collection ", function(err, collection){
collection.find({}).toArray(function(err, data){
console.log(data); // data printed in console
})
});
});
I tried all the answers but nothing worked out, finally got the answer hoe to do it.
var mongoose = require('mongoose');
mongoose.connect('mongodb://0.0.0.0:27017/local');
// let model = require('./test1');
setTimeout(async () => {
let coll = mongoose.connection.db.collection(<Your collection name in plural form>);
// let data = await coll.find({}, {limit:2}).toArray();
// let data = await coll.find({name:"Vishal"}, {limit:2}).toArray();
// let data = await coll.find({name:"Vishal"}, {projection:{player:1, _id:0}}).toArray();
let data = await coll.find({}, {limit:3, sort:{name:-1}}).toArray();
console.log(data);
}, 2000);
I have also mentioned some of the criteria to filter out. Delete and update can also be done by this.
Thanks.
Make sure you're connecting to the right database as well as the right collection within the database.
You can include the name of the database in the connection string.
notice databasename in the following connection string:
var mongoose = require('mongoose');
const connectionString = 'mongodb+srv://username:password#hosturl.net/databasename';
mongoose.connect(connectionString);