MongoDb : MongoDb no SQL

Mongo

Note : For Mongo Cloud

• Set Password: Select Cluster > Security >Select User > Edit
• Add IP : Select Cluster > Security > Network Access > Add IP Address

ref:

• https://onecompiler.com/

SQL VS MongoDB

• Database = Database
• Tables = Collections
• Rows = Documents

Pre-Req:

• Install Docker

Steps:

1. Open Terminal

2.    docker run -d -p 27017:27017 mongo
      docker ps -a
      docker exec -it <containerid> bash
      $mongosh
   

3. CRUD

      // Comment
      use test
      
      db.createCollection("T")
      
      show tables
      
      //insert into T (sl,name,age) values (1,'Ram,10)
      db.T.insertMany([{sl: 1,name: "Ram",age: 10} , {sl: 2,name: "Sam",age: 8} ])
      
      //update T set age=11 where name='Ram'
      db.T.updateMany({ name: 'Ram'},{ $set: { age: 11 } });
      
      //delete from T where name ='Ram'
      db.T.deleteMany({ name: "Ram" })
   

4. Select
   show tables

     // select * from T
     db.T.find() 
     
     //select sl,name from posts 
     //1 = show 
     db.T.find({}, {sl: 1, name: 1 })
     
     //select * from T where name='Ram'
     db.T.find({name: 'Ram'})
     
     //select * from T where age>=3.5
     db.T.find({age: {$gte: 11}})
     
     db.T.find(
     {$and: [
               { $or: [{age: {$lt : 10 }}, {sl : { $gt: 1 }}   ]},
               { $or: [{ age: 11 }, {sl : { $lt : 100 }} ]}
     ]
     })
   

Operators

compare values:

• $eq (equal): db.inventory.find( { quantity: { $ne: 20 } } )
• $ne (not equal)
• $gt (greater than )
• $gte (greater than or equal )
• $lt (less than)
• $lte (less than or equal )
• $in(matched within an array)

Logical

• $and: Returns documents where both queries match
• $or: Returns documents where either query matches
• $nor: Returns documents where both queries fail to match
• $not: Returns documents where the query does not match

Evaluation

• $regex: Allows the use of regular expressions when evaluating field values
• $text: Performs a text search
• $where: Uses a JavaScript expression to match documents

Update

• $currentDate: Sets the field value to the current date
• $inc: Increments the field value
• $rename: Renames the field
• $set: Sets the value of a field
• $unset: Removes the field from the document

Update Array

• $addToSet: Adds distinct elements to an array
• $pop: Removes the first or last element of an array
• $pull: Removes all elements from an array that match the query
• $push: Adds an element to an array

Python

from pymongo import MongoClient
client = MongoClient("mongodb://localhost:27017/") 
db = client['test']   #Creates DB if not exists
if "C" not in db.list_collection_names():
        db.create_collection("C")
db["C"].insert_one({"c":2,"d":3})
for i in db["C"].find():print(i)

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