MongoDB insertMany() document size | How to check maxWriteBatchSize in MongoDB

insertMany() function in MongoDB accepts array of objects and can insert multiple documents in the collections. Here is the syntax for insertMany() function:-

db.collection.insertMany(
   [ <document 1> , <document 2>, ... ],
   {
      writeConcern: <document>,
      ordered: <boolean>
   }
)

db.collection.insertMany(

[ <document 1> , <document 2>, ... ],

{

writeConcern: <document>,

ordered: <boolean>

}

)

The number of operations in each group cannot exceed the value of the maxWriteBatchSize of the database.

This can be checked by running the below query.

db.runCommand( { hello: 1 } ).maxWriteBatchSize

1	db.runCommand( { hello: 1 } ).maxWriteBatchSize

insertMany() document size

You also can check other configurations by running this command, for example is you database is in read only mode, if isWritablePrimary is true then instance is primary in replica set. ... Read More

MongoDB - Update objects in a document's array | MongoDB update object in Array

Sometime in MongoDB, we need to update the object in the array for the particular matching document. We need to update either the first matching object or all the matching objects in the array. Let me give you an example of the documents. Let say I have the following collection whose name is items.

[
{
    "_id" : ObjectId("4faaba123412d654fe83hg876"),
    "user_id" : 123456,
    "total" : 130,
    "items" : [
            {
                    "item_name" : "my_item_one",
                    "price" : 20
            },
            {
                    "item_name" : "my_item_two",
                    "price" : 50
            },
            {
                    "item_name" : "my_item_three",
                    "price" : 60
            }
    ]
}
]

[

{

"_id" : ObjectId("4faaba123412d654fe83hg876"),

"user_id" : 123456,

"total" : 130,

"items" : [

{

"item_name" : "my_item_one",

"price" : 20

{

"item_name" : "my_item_two",

"price" : 50

{

"item_name" : "my_item_three",

"price" : 60

}

]

}

]

Now I wanted to update the latest price of the item whose name is "my_item_two".

We achieve this through the positional operator ($). The positional operator is used to performing the operation on the particular position. Let me write the query for that:

db.items.update(
    // Match criteria
    {
        user_id: '123456',
        'items.item_name': 'my_item_two'
    },

    // Update first matching array element using the positional operator ($)
    {
        $set: {
            'items.$.price': 60,
        }
    }
)

db.items.update(

// Match criteria

{

user_id: '123456',

'items.item_name': 'my_item_two'

// Update first matching array element using the positional operator ($)

{

$set: {

'items.$.price': 60,

}

)

This will update the first matching array element but sometime we may need to update all the matching array elements and we can do that by using the $[]. The all positional operator $[] indicates that the update operator should modify all elements in the specified array field.

db.items.updateMany(
    // Match criteria
    {
        user_id: '123456',
        'items.item_name': 'my_item_two'
    },

    // Update all matching array element using the positional operator ($)
    {
        $set: {
            'items.$[].price': 60,
        }
    }
)

db.items.updateMany(

// Match criteria

{

user_id: '123456',

'items.item_name': 'my_item_two'

// Update all matching array element using the positional operator ($)

{

$set: {

'items.$[].price': 60,

}

)

MongoDB find match in array of objects || MongoDB where condition with array of objects | $elemMatch or dot notation match

In MongoDB, $elemMatch and dot notation are used to find the match in the array of objects. But both have some difference.
Let me explain this with an example. Let say we have a document like:

db.classes.insert([{
    "_id" : 1,
    "name" : "Class 10",
    "students" : [  
        { "rollNo" : 1, "name" : "Saurabh", "score" : 65, "section" : "A" },
        { "rollNo" : 2, "name" : "Gaurav", "score" : 90, "section" : "B" },
        { "rollNo" : 3, "name" : "Mrigank", "score" : 75, "section" : "C" }       
        ]
},
{
    "_id" : 2,
    "name" : "Class 11",
    "students" : [  
        { "rollNo" : 1, "name" : "Satendra", "score" : 88, "section" : "B" },
        { "rollNo" : 2, "name" : "Shakshi", "score" : 91, "section" : "A" },
        { "rollNo" : 3, "name" : "Sachin", "score" : 82, "section" : "A" },
        { "rollNo" : 4, "name" : "Urvi", "score" : 55, "section" : "C" }        
        ]
},
{
    "_id" : 3,
    "name" : "Class 12",
    "students" : [  
        { "rollNo" : 1, "name" : "Radha", "score" : 77, "section" : "B" },      
        { "rollNo" : 2, "name" : "Geeta", "score" : 81, "section" : "A" }       
        ]
}])

db.classes.insert([{

"_id" : 1,

"name" : "Class 10",

"students" : [

{ "rollNo" : 1, "name" : "Saurabh", "score" : 65, "section" : "A" },

{ "rollNo" : 2, "name" : "Gaurav", "score" : 90, "section" : "B" },

{ "rollNo" : 3, "name" : "Mrigank", "score" : 75, "section" : "C" }

]

{

"_id" : 2,

"name" : "Class 11",

"students" : [

{ "rollNo" : 1, "name" : "Satendra", "score" : 88, "section" : "B" },

{ "rollNo" : 2, "name" : "Shakshi", "score" : 91, "section" : "A" },

{ "rollNo" : 3, "name" : "Sachin", "score" : 82, "section" : "A" },

{ "rollNo" : 4, "name" : "Urvi", "score" : 55, "section" : "C" }

]

{

"_id" : 3,

"name" : "Class 12",

"students" : [

{ "rollNo" : 1, "name" : "Radha", "score" : 77, "section" : "B" },

{ "rollNo" : 2, "name" : "Geeta", "score" : 81, "section" : "A" }

]

}])

Now let me find the class name whose students has scored greater than 86.

If using the dot notation then here is the example:

db.classes.find({'students.score':{'$gt':86}},{_id:0, 'name':1);

1	db.classes.find({'students.score':{'$gt':86}},{_id:0, 'name':1);

The result will be :

{ "name" : "Class 10" }
{ "name" : "Class 11" }

1 2	{ "name" : "Class 10" } { "name" : "Class 11" }

Now If I find the class name whose students has scored greater than 86 and their section is A by using dot notation.

db.classes.find({'students.score':{'$gt':86},'students.section':'A'},{_id:0, 'name':1);

1	db.classes.find({'students.score':{'$gt':86},'students.section':'A'},{_id:0, 'name':1);

The result will be:

{ "name" : "Class 10" }
{ "name" : "Class 11" }
{ "name" : "Class 12" }

{ "name" : "Class 10" }

{ "name" : "Class 11" }

{ "name" : "Class 12" }

Hence if we are using dot notation, Any condition match in students array, like score or section will be returning document.

But what if we wanted to match every condition? The answer is: We use $elemMatch for that. ... Read More

Push multiple objects into MongoDB array document | Append Multiple Objects to an Array in MongoDB

Normally we use $push to push or append the element or object into an array in mongoDB. But sometime we may need to push the multiple objects into mongoDB array document. Here below I'll try to explain how we can do that.

Let say I have a collection of favorite products and the collection name is favorite_products.

{
                'productId':123,
                'users':[
                        {'id':1,'name': 'saurabh'}, 
                        {'id':2,'name': 'gaurav'}, 
                        {'id':3,'name': 'coding4developers'}
                ]
        },
        {
                'productId':124,
                'users':[
                        {'id':4,'name': 'pankaj'}, 
                        {'id':2,'name': 'gaurav'}
                ]
        }

{

'productId':123,

'users':[

{'id':1,'name': 'saurabh'},

{'id':2,'name': 'gaurav'},

{'id':3,'name': 'coding4developers'}

]

{

'productId':124,

'users':[

{'id':4,'name': 'pankaj'},

{'id':2,'name': 'gaurav'}

]

}

Now in the above document, I wanted to push/append the multiple user objects into the users array whose product id is 124.

MongoDB distinct with array of objects | Getting distinct values from object array MongoDB

Let say we have a collection transactions which contains some document and documents contain payments which is array of objects.
Now my task is to get the unique types in payments array of every document.

{
        'id':'74656345'
        'payments':[
                {
                        'amount': 200,
                        'type': 'Debit Card'
                },
                {
                        'name': 300,
                        'type': 'Internet Banking'
                },
                {
                        'name': 300,
                        'type': 'Credit Card'
                }
        ],
        
},
{
        'id':'9783475'
        'payments':[
                {
                        'amount': 200,
                        'type': 'Debit Card'
                },
                {
                        'name': 300,
                        'type': 'Internet Banking'
                },
                {
                        'name': 300,
                        'type': 'UPI'
                }
        ],
        
}

{

'id':'74656345'

'payments':[

{

'amount': 200,

'type': 'Debit Card'

{

'name': 300,

'type': 'Internet Banking'

{

'name': 300,

'type': 'Credit Card'

}

{

'id':'9783475'

'payments':[

{

'amount': 200,

'type': 'Debit Card'

{

'name': 300,

'type': 'Internet Banking'

{

'name': 300,

'type': 'UPI'

}

Expected Result: Debit Card, Internet Banking, Credit Card, UPI

which is unique values of payment types in transctions collection and the MongoDB query for that is given below:

db.transctions.aggregate(
    {'$unwind':'$payments'},
    {"$group" : {"_id": "$payments.type"}}
)

db.transctions.aggregate(

{'$unwind':'$payments'},

{"$group" : {"_id": "$payments.type"}}

)

Here we first unwind the data so that every payments array can be converted to objects and then we are grouping the type of payments document in transctions collection. ... Read More

Create or Insert Operation in MongoDB

a) db.collection.insert() - Version 2.6

db.products.insert( 
{
name: "Coding 4 Developers",
email: "info@www.coding4developers.com"
} )

db.products.insert( [
{ item: "Wingy Kart", qty: 15 },
{ item: "Wingy Kart", qty: 20 },
{ item: "Wingy Kart" , qty: 30 }
] );

db.products.insert(

{

name: "Coding 4 Developers",

email: "info@www.coding4developers.com"

} )

db.products.insert( [

{ item: "Wingy Kart", qty: 15 },

{ item: "Wingy Kart", qty: 20 },

{ item: "Wingy Kart" , qty: 30 }

] );

b) db.collection.save() - Version 2.6

The save() method uses either the insert or the update command. If record already exit the it updates else insert the new document.

db.products.save( { item: "Wingy kart", qty: 20 } )

1	db.products.save( { item: "Wingy kart", qty: 20 } )

c) db.collection.insertOne() - Version 3.2

db.user.insertOne(
{
name: "Coding 4 Developers",
email: "info@www.coding4developers.com"
}
)

db.user.insertOne(

{

name: "Coding 4 Developers",

email: "info@www.coding4developers.com"

}

)

d) db.collection.insertMany() - Version 3.2

db.products.insertMany( [
{ item: "Wingy Kart", qty: 15 },
{ item: "Wingy Kart", qty: 20 },
{ item: "Wingy Kart" , qty: 30 }
] );

db.products.insertMany( [

{ item: "Wingy Kart", qty: 15 },

{ item: "Wingy Kart", qty: 20 },

{ item: "Wingy Kart" , qty: 30 }

] );

What is the use of MongoDB or When to use MongoDB ?

MongoDB is mostly used as the primary data store for operational applications with real-time requirements . MongoDB is easy to operate and scale in ways that are hard if not impossible with relational databases.
In many use cases where relational databases aren’t a good fit, like applications with unstructured, semi-structured and polymorphic data, as well as applications with large scalability requirements or multi-data center deployments so in that case MongoDB is the best option to choose.
MongoDB may not be a good fit for some applications. For example, applications that require complex transactions and scan-oriented applications that access large subsets of the data most of the time may not be a good fit for MongoDB. MongoDB is not a drop-in replacement for legacy applications built around the relational data model and SQL.
Some common use cases include mobile apps, product catalogs, real-time personalization, content management, logging and applications delivering a single view across multiple systems.

...

Node JS with mongoose | Create schema | Save data to mongodb in node js

To install the mongoose:

npm install mongoose

1	npm install mongoose

routes/post.js

var express = require('express');
var router = express.Router();
var Post = require('../schema/post');

/* GET post page. */
router.get('/', function(req, res, next) {
res.render('post', { title:'Post' });
});


/* POST Data. */
router.post('/', function(req, res, next) {
console.log(req.body);
var data = newPost(req.body);
data.save(function(err){
if(err){
res.render('post', { title:'Hey', message:'Invalid request!' });
} else {
res.render('post', { title:'Hey', message:'Request received!' });
}
})
});

module.exports = router;

var express = require('express');

var router = express.Router();

var Post = require('../schema/post');

/* GET post page. */

router.get('/', function(req, res, next) {

res.render('post', { title:'Post' });

});

/* POST Data. */

router.post('/', function(req, res, next) {

console.log(req.body);

var data = newPost(req.body);

data.save(function(err){

if(err){

res.render('post', { title:'Hey', message:'Invalid request!' });

} else {

res.render('post', { title:'Hey', message:'Request received!' });

}

})

});

module.exports = router;

MongoDB connection using mongoose with node JS: Write the following code in app.js

// DB connection
var mongoose = require('mongoose');
mongoose.Promise = global.Promise;
mongoose.connect('mongodb://localhost/my_database')
.then(() => console.log('connection succesful'))
.catch((err) => console.error(err));
// DB connection end

// DB connection

var mongoose = require('mongoose');

mongoose.Promise = global.Promise;

mongoose.connect('mongodb://localhost/my_database')

.then(() => console.log('connection succesful'))

.catch((err) => console.error(err));

// DB connection end

Create schema for blog post: schema/post.js

var mongoose = require('mongoose');
var Schema = mongoose.Schema,
ObjectId = Schema.ObjectId;
var BlogPost = new Schema({
name :String,
email :String,
message :String
});
module.exports = mongoose.model('Post', BlogPost);

var mongoose = require('mongoose');

var Schema = mongoose.Schema,

ObjectId = Schema.ObjectId;

var BlogPost = new Schema({

name :String,

email :String,

message :String

});

module.exports = mongoose.model('Post', BlogPost);

View : views/post.js

<% if (typeof message != 'undefined' && message) { %>
<h2><%= message %></h2>
<% } %>
<form class="form-horizontal" role="form" style="width: 50%;" method="post" action="">
<div class="form-group">
<label for="name"class="col-sm-2 control-label">Name</label>
<div class="col-sm-10">
<input type="text"class="form-control"id="name"name="name"placeholder="First & Last Name"value="">
</div>
</div>
<div class="form-group">
<label for="email"class="col-sm-2 control-label">Email</label>
<div class="col-sm-10">
<input type="email"class="form-control"id="email"name="email"placeholder="info@www.coding4developers.com"value="">
</div>
</div>
<div class="form-group">
<label for="message"class="col-sm-2 control-label">Message</label>
<div class="col-sm-10">
<textarea class="form-control"rows="4"name="message"></textarea>
</div>
</div>
 
<div class="form-group">
<div class="col-sm-10 col-sm-offset-2">
<input id="submit"name="submit"type="submit"value="Send"class="btn btn-primary">
</div>
</div>
 
</form>

<% if (typeof message != 'undefined' && message) { %>

<% } %>

</div>

<label for="email"class="col-sm-2 control-label">Email</label>

</div>

<label for="message"class="col-sm-2 control-label">Message</label>

</div>

</div>

</form>

What is MongoDB?

What is MongoDB? and Why MongoDB?

MongoDB is a cross-platform, document oriented database that provides, high performance, high availability, and easy scalability. MongoDB works on concept of collection and document. MongoDB is leading NoSQL database which is written in C++ and stores data in the form JSON.

How to install mongo db on mac

1)To install brew

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Or to update brew

brew update

2) To install mongodb

brew install mongodb

Coding 4 Developers

Running Code Website

Category: Mongo DB

MongoDB insertMany() document size | How to check maxWriteBatchSize in MongoDB

MongoDB - Update objects in a document's array | MongoDB update object in Array

MongoDB find match in array of objects || MongoDB where condition with array of objects | $elemMatch or dot notation match

Push multiple objects into MongoDB array document | Append Multiple Objects to an Array in MongoDB

MongoDB distinct with array of objects | Getting distinct values from object array MongoDB

Create or Insert Operation in MongoDB

What is the use of MongoDB or When to use MongoDB ?

Node JS with mongoose | Create schema | Save data to mongodb in node js

What is MongoDB?

How to install mongo db on mac

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