pymongo

MongoDB shell acts as a client to perform our required database operations.
MongoDB shell is JavaScript based- special applications to communicates with MongoDb server
From Python Program to communicate with mongoDB database some special software must be required, which is nothing but Driver software i.e by using Driver Software Python program can communicated with MongoDB Database
Python Driver Software is: Python Library
To implement mongo this website is good https://mongoplayground.net/
To delete all the records db.collectionname.deleteMany()

pip => Package manager in Python

By default pymango is not available, we have to install separatly by using commands

How to install pymongo

pip install pymongo

Important steps in python to MongoDB communication

Import pymango module in our python program

import pymongo or from pymongo import *
Create client to communicate with mongoDB Server
1. client = pymongo.MongoClient()
2. client = pymongo.MongoClient('localhost',27017) IP => localhost, PORT => 27017
3. client = pymongo.MongoClient()
Create/Connect with databse

empDB = Client['employeeDB]
Create/Connect with collection empCollection = empDB.employees
By using collection object we can perform required databse operations.
- To insert Documents :
  empCollection.insert_one({}) => Highly Recommended empCollection.insert_many()
  empCollection.insert() => debrecated
- To find Documents :
  empCollection.find_one()
  empCollection.find()
- To Update Documents :
  empCollection.update_one()
  ->recommended empCollection.update_many()
  empCollection.update()
- To delete Document:
  empCollection.delete_one()
  empCollection.delete_many()
  empCollection.delete()
- Close Client => Highly Recommended
  client_close()
If we getting this error while retriving _id use str() function to type cast

To perform schema validation first we need to

edit set admin to builtin role in mongo db atlas in database access clink
then we have to set &authSource=admin" at the end of connections string

db.dropdatabase()

eg-1

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

document = {
    'Eno': 100,
    'Ename': 'ASHISH',
    'ESAL': 10000000,
    'eaddr': "Punjab"
}

empCollection.insert_one(document)

print('Document Inserted Successfully!!!')
client.close()

```py tittle="eg-2" import pymongo client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

document = empCollection.find_one() print(type(document)) # dict print(document)

print(document.get('Eno'))

client.close()

## Write a python scrpt to connnect with MongoDB and display all available databases?
```py
# we have o use clicent.list_database_names() method
import pymongo

client = pymongo.MongoClient()
db_list = client.list_database_names()

print('The Available Database are ')
print('#'*40)

for db in db_list:
    print(db)

client.close()

# output
The Available Database are 
########################################
# My_Database
# admin
# chatflowdb
# config
# job_recom_db
# local

WAP to create a database named woth python and in that database create a collection named with employees and insert on document?

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

document = {
    'Eno': 100,
    'Ename': 'ASHISH',
    'ESAL': 10000000,
    'eaddr': "Punjab"
}

empCollection.insert_one(document)

print('Document Inserted Successfully!!!')
client.close()

# Document Inserted Successfully!!!

To insert multiple documents :

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

emplist =[
    {
    'Eno': 101,
    'Ename': 'sonu',
    'ESAL': 10000000,
    'eaddr': "up"
    },  {
    'Eno': 102,
    'Ename': 'krishna',
    'ESAL': 50000000,
    'eaddr': "delhi"
    },  {
    'Eno': 103,
    'Ename': 'vivek',
    'ESAL': 99000,
    'eaddr': "mp"
    },  {
    'Eno': 104,
    'Ename': 'duby',
    'ESAL': 800000,
    'eaddr': "j&k"
    },
]

empCollection.insert_many(emplist)

print('All Documents Inserted Successfully!!!')
client.close()
print(f'{len(emplist)}')

# output
# All Documents Inserted Successfully!!!
# 4

Read Dynamic Data from the end user & inserted into database

db.employees.deleteMany({}) => delete all data

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

while True:
    Eno = int(input("Enter eno "))
    Ename = input("enter ename ")   
    ESAL = float(input("enter esalary "))    
    eaddr = input("enter address ")  

    document = {
        'Eno': Eno,
        'Ename': Ename,
        'ESAL': ESAL,
        'eaddr': eaddr
        }

    empCollection.insert_one(document)
    print('Document Inserted Successfully!!!')

    option = input("Do you want to insert more ").lower()

    while option not in ('y','yes','n','no') :
        option = input("Invalid Option, [yes/no] ").lower()

    if option in ('no','n'):
        break

print("Thanks")

client.close()

# output
# Rnter eno 106
# enter ename aa
# enter esalary 21321
# enter address asdsa
# Document Inserted Successfully!!!
# Do you want to insert moreno
# Thanks

Note:

insert() method is deprecated and hence it is not recommened to use instead. We can use inset_one() or insert_many() methods.

## Find Operation: 1. find_one() 2. find()

find_one()
- return python dict object
- to find only one matched document
find()
- all match documents to find
- it return cursor object

5. To find only one document

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

document = empCollection.find_one() 
print(type(document)) # dict

print(document.get('Eno'))

client.close()

To find multiple documents

WAP to display all documents from employees collections
here we have to use find() method.

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

empcursor = empCollection.find() 
print(type(empcursor)) 

for document in empcursor:
    print(type(document))
    print(f"{document.get('Eno')}")
client.close()

# output
# <class 'pymongo.cursor.Cursor'>
# <class 'dict'>
# 100
# <class 'dict'>
# 101
# <class 'dict'>
# 102
# <class 'dict'>
# 103
# <class 'dict'>
# 104
# <class 'dict'>
# 100

To find all employees whose salary is grater than 1500

shell => db.employee.find({'esal':{\(gt:1500}}) python => empcollection.find({'Esal':{'\)gt' 1500}})

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

empcursor = empCollection.find({'ESAL': {'$gt': 99000}}) #'' is required

print("*"*33)
for document in empcursor:
    print(f"{document.get('ESAL')}")

client.close()

# output
# *********************************
# 10000000
# 10000000
# 50000000
# 800000
# 10000000

8 To find employees information based on descending order of salary?

shell : db.employees.find().sort({'ESAL': -1})

python : empCollection.find().sort('ESAL', -1) - sort => take 2 arguments second one is dicrection

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

empcursor = empCollection.find().sort('ESAL',-1)

print("*"*33)
for document in empcursor:
    print(f"{document.get('Eno')} {document.get('Ename')} {document.get('ESAL')} {document.get('eaddr')}")

# client.close()
# *********************************
# 102 krishna 50000000 delhi
# 100 ASHISH 10000000 Punjab
# 101 sonu 10000000 up
# 100 ASHISH 10000000 Punjab
# 104 duby 800000 j&k
# 103 vivek 99000 mp

9. To display 3 employee information who are having least salary

shell : db.employee.find().sort({'ESAL': 1}).limit(3) python : empCollection.find().sort('ESAL', 1).limit(3)

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

empcursor = empCollection.find().sort('ESAL',1).limit(3)

print("*"*33)
for document in empcursor:
    print(f"{document.get('Eno')} {document.get('Ename')} {document.get('ESAL')} {document.get('eaddr')}")

client.close()

# *********************************
# 103 vivek 99000 mp
# 104 duby 800000 j&k
# 100 ASHISH 10000000 Punjab

10. Display employee info based on given emp name ?

document = empCollection.findOne({"Ename": name})

import pymongo
client = pymongo.MongoClient()

db = client['pythondb'] # pythondb is db name

empCollection = db.employees # Collection name

document = empCollection.find_one({"Ename": "ASHISH"})
if document:
    print(f"{document.get('Eno')} {document.get('Ename')} {document.get('ESAL')} {document.get('eaddr')}")
else:
    print("element not find")
client.close()

# output
# 100 ASHISH 10000000 Punjab