MongoDB

Humongous: - extremely large: Huge a humongous building humongous amounts of money. - To handle a very huge amount of data if we want a database, then go for mongodb

Intro

MongoDB is the most popular and trending database.
The vendor: MongoDB
https://www.mongodb.com/

Where we can use mongoDB

For desktop applications, for mobile applications
For web applications, this database is more popular
Full stack developer

stack

The technologies which can be used to devlop web application are called a stack.

The most popular stack: 1. MEAN Stack 2. MERN Stack

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It is js based web application

MERN /MEAN

MongoDB — document database
Express(.js) — Node.js web framework
React(.js)/ Angular — a client-side JavaScript framework
Node(.js) — the premier JavaScript web server

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React / Angular is a frontend framework.
Express.js is the Backend server framework.
Node.js is responsible to provide server side runtime environment
MongoDb is database

By using MEAN and MEAN Stack, we can build javascript based web application. 1) Node.js is based on javascript 2) React / Angular is based on javascript 3) Express.js is based on javascript 4) MongoDb is based on javascript

MongoDB internally uses Mozilla's spider Monkey javaScript Engin

Q3) What is the type of mongoDB

It is Document database / NoSQL database
NoSql = > Not only SQL

Relational database Vs Document Database

There are two most common types of databases

Relational databases / SQL databases
Document databases / NoSql database

Relational databases/SQL databases
The total data sore in the form of table
table based on fixed schema eg employee(eno,ename,esal,eaadr)
The data will be stored in table, and these tables have fixed schma(structure)
The data stored in tables has relationship like:
1. one to one
2. one to many
3. many to one
4. many to many
To retrieve data from a relational database, we have to write join queries that collect data from different tables
- eg Oracle, Mysql etc
Document Database / NoSQL Database
Each DB contains multiple collections
Inside each collection there are multiple documents
Each document is just like a row
Our data stored in document such type of db called document oriented or document
each document is independent of the other
Data will be stored in separate documents and each document is indecent of others
- mongodb it not having fixed schema

MongoDB structure

MongoSB physical database contains several logical database
Each database contains several collections. Collection is something like table in a relation database.
Each collection contains several documents. Document is something like record/ row in a relational database
eg
Database: Shopping cart database
collections: Customer, Products, Order
Customer Collection Contains several documents

document1:{
         "name": "Sunny",
         "age": 40,
         "salary": 10000,
       }

Q How data represent in mongoDB?

In JSON (BSON) format
JSON => JavaScript Object Notation (Biggest advantage of mongo)
Bson => Binary JSON
The document will be stored in Binary Form

Key characters of MongoDB database

All information related to a document will be stored in a single place.
To retrieve data, it is not required to perform join operations, hence retrival is very fast
Documents are independent of each other and no schema. Hence, we can store unstructured data like video, audio files, etc.
We can perform operation lie editing existing document, deleting document and inserting a new document very easily
Retrival data is in the form of json which can be understandable ny any programing language without any conversion (Interoperability)
We can store a very huge amount of data and hence scalability is more

Note: performance and flexibility are the biggest assets of mongodb

popular NOSQL

MongoDB
Cassandra
Elasticsearch
Neo4J
HBase
redis.io

If we install mongodb, we will get two things:

Mongodb shell
Mongodb server

These are separate javascript based application

Mongodb shell Vs Mongodb server

Once we install Mongodb, we will get Mongodb shell and Mongodb server. These are javascript based application

Mongodb server role

Store data in Mongodb database.it is responsible to sore our data in database

Purpose of shell

Shell can be used to manage mongodb server
Mongo shell is responsible to manage server
By using this shell we can perform all required CRUD operation.
c => create
R => Read
U => Update
D => Delete

alt text - Mongodb server can be either local or remote - To launch / start mongo server = > Mongod command - To launch / start mongo shell = > Mongo command

GUI support is also there for mongodb shell => mongodb compass

Mongo Driver

alt text If we want to communicate with database special software need like a driver - From application(C#,python, java,node.js) if we want to communicate with a database some special software must be required which is nothing but driver software

pymongo is a recommended way to work with MongoDB for python

Some shell commands

 show dbs
 show collactions

 db.stats()
 db.version()
 db.help()

mongod -version to perform an operation on server => mongod --dbpath "c:\data\db" - Py mongo is recommended way to work with MongoDB from python - 27017 => Default Port Number - mongo.exe/mongosh.exe => shell - mongod.exe => server - if we enter mongod in cmd it will get path error ("NonExistentPath - db") - create a path "c:\data\db"

Default Database:

MongoDB admin use these default database

show dbs - admin - config - local

1. admin

adminDB is used store user authentication and authorization information like userna,e, passwords roles etc
This database is used by adminstrator which creating,deleting and uploading user and while assining roles

2. Config:

To store configuration information of mongodb server like which part its listing

3. local (clone a DB)

Replica
localDB can be used by admin while performing replication process

We can store very huge amount of data and hence scalibilty is more

Data Formats in MongoDB

JSON : {name: "ashish"} => BSON and that BSON will be storted

Why BSON

1). In JavaScript only 6 types are available 1. string 2. Number 3. Object 4. Array 5. Boolean 6. Null

But Bson provides some extra types also like - 32 Bit Integer => Numerical - ObjectID => JSON =>10kb - Date => BSON 4 to 5 kb

BSON required less memory
End user / Developer will provide data in json formate
In mongoDb server data will be stored in BSON form

Note:

Efficient storage and extra data types are specicilty of BSON over JSON

EJSON => Extended JSON At the time of retrieval BSON Data will be converted to EJSON for Understend puroperly

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Insertion of Document / Creation = JSON to BSON
Read Operation / Retrieval operation = BSON to JSON

Q What data formaat used in MongoDB - Three (3) Formats JSON, BSON, EJSON

### Creation of database and collection - Database will be created dynamically - Whenever we are creating collection or inserting document then database will be created dynamically

### How to create collection

 use ashishDB
db.createCollection("employees") # Should be camel-case

### How to drop collection

db.collection.drop()
db.student.drop()

### How to drop database

 db.dropdatabase()
 db.studentdb.drop() # current database will be deleted

Basic CRUD operation in simple way

C => Create / Insert document

   db.collection.inserOne()
   db.collection.inserMany()
   db.collection.insertOne({ name: "Alice", age: 25 })
   db.collection.insertMany([{ name: "Bob", age: 30 }, { name: "Charlie", age: 22 }])

   db.collection.inser()
      Collection.insert() # is deprecated.

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Additional Methods for Inserts The following methods can also add new documents to a collection:

   db.collection.updateOne() # when used with the upsert: true option.

   db.collection.updateMany() # when used with the upsert: true option.

   - db.collection.findAndModify() # when used with the upsert: true option.

   - db.collection.findOneAndUpdate() # when used with the upsert: true option.

   db.collection.findOneAndReplace() # when used with the upsert: true option.

   db.collection.bulkWrite().
   db.collection.bulkWrite() # MongoDB provides the ability to perform write operations in bulk.

R => Read / Retrieval operation

db.collection.find() # To get all documents present in the given collection.<br>
db.collection.dindOne() # To get one document<br>
db.find().pretty()

3) Update => Update Operation

   db.collection.updateOne()
   db.collection.updateMany()
   db.collection.replaceOne()

- Old value will relace with new - If Filed is not already there it will create and update operation document must one atomice operation $ => predefine {$set{sal:1000}}

Note: If anything prefixed with$ symbol, then it is predfine word in MongoDB

4) D => Delete opration

   db.collection.deleteOne()
   db.collection.deleteMany()

Note Datbase and collection will be created dynamically whenever we are creting document.

Capped Collection

   db.createCollection(name,options) # p1 = max, size ,document
   db.createCollection("emp",{capped:true, size:3736578,max:100})

- Old document will be deleted automatically Based on time stemp - If capped is true meaning that if size exceeds or maximum number of document reached, then oldest entry will be deleted automatically.

   db.createCollection("emp") # Normal Collection
   db.createCollection("emp",{capped:true}) # Invalid 
   # without  size,max we cannot created capped collection
   db.createCollection("emp",{capped:true, size:36734543}) # valid
   db.createCollection("emp",{size:3676934})` # Invalid
      #"errorM$g": the capped filed needs to be true eithere thr size or max filed.
   db.createCollection("emp",{capped:true, size:3343455453,max:10000}) # valid

Q What is capped collection?

If size exceeds or maximum numbers of documents reached then oldest entry will be deleted automatically, such type of collection are called capped

By Default in MongoDB there is no schema but we can stil define schema

Inserting Documents in the collection (C => Create)

   db.collection.inserOne() # Highly Recommeneded
   db.collection.inserMany() # Highly Recommeneded
   db.collection.inser() # Deprecated

db.collection.inserOne()

   db.employee.InsertOne({})`
   # Argument is only one javascript object<br>

   db.employee.insertOne({eno:100,ename:"ashish"})`

db.collection.inserMany()

To inset multiple documents we need to pass array of javascript object

   db.collection.insertMany([{},{}])
   db.collection.insertMany([{eno:102,ename:"sonu"},{eno:103,ename:"kumar"}])

db.collection.inser()

To insert either a single document or multiple

   db.collection.inser({})
   db.collection.inser([{}])
   db.employee.inser()

Creating Document separtly & inserting into collection

      var emp = {};
      emp.eno = 7777;
      emp.ename = "SUNNY";
      emp.esal = 7777777;
      mp.eaddr = "yhd";
      emp = { 
            eno: 7777, 
            ename: 'SUNNY', 
            esal: 7777777, 
            eaddr: 'yhd' 
         }

      db.employees.insertMany([emp])

      db.employees.insertOne(emp)
      db.employees.insertMany([emp])
      db.employees.insert(emp)
      db.employees.insert([emp])

Inserting Document from JavaScript file

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Inserting Document from JSON file (Mongo Import Tool)

In JSON file, the data should be in array form make size the data should be of json only

javaScript vs json

In JavaScript object, quote symbols for keys are optional but in JSON quote symbols are mandatory for keys

db.collection.insertOne(javaScript Object) javaScript Object => Quote symbol are optional

Mongod => Tool to start mongoDB server
Mongosh => Tool to start MongoDB shell
MongoImport => Tool to Import documents from JSON file into MongoDB

mongoImport is not available bydefault we have to make avalable mannualy.

Note:

MongoImport command should be executed from the Command prompt but not from shell

mongoimport --db database Name --collectionName --fileName --JSON array

Note:

Similerly we can use mongoImport data from csv file