Read data from mongodb in nodejs

 

 

 

 

Post API insert data in MongoDB

This blog and in upcoming blog we will see mongodb basic and how is it work with installation and after installation we should not face any problem while making Database, collection(table) and using the data in nodejs even whenever we will make API. Read data from mongodb in nodejs

• # Read Data from MongoDB
  
• # Make file for db connection
  
• # Handle Promise 

 

Now in this blog we will consider about mongoDB basic command which we can use to create Database, collection etc.

 

 What is MongoDB

 

MongoDB is a popular open-source NoSQL (non-relational) database management system. NoSQL means no structure like it is look like an object while in SQL it is a structure query language like SELECT CustomerName, City FROM Customers; (The SELECT statement is used to select data from a database.) But NoSQL database is useless...NOT completely because of whenever we want add extra column in database then it is possible through NoSQL MongoDB.   

 

MongoDB installation - CLICK HERE

MongoDB Basic Command - CLICK HERE

About MongoDB vs SQL - CLICK HERE

CRUD in MongoDB - CLICK HERE

 

 

Object Like - 

 

 

{
  "_id": {
    "$oid": "659ad46e0382148123c82841"
  },
  "name": "moto G60",
  "brand": "motorola",
  "price": 16500,
  "category": "mobile"
}

 

 

MongoDB is a type of database that helps store and manage large amounts of data in a flexible and scalable way. Unlike SQL, MongoDB doesn't require a fixed structure for the data, allowing you to store information in a more versatile format.

• MongoDB is a NoSQL database.
• The data stored in a collection
• Collection don't have row and columns
• Data is stored in the form of object.

 Read Data from MongoDB

 

if you remember, we wrote the code for database connection and data reading in the same file. if you write coding of insert, update, delete in same function and same file then it will be very complex. so that's why we will separate file of mongoDB connection file.

 

First you need to create folder for mongoDB connection and inside this folder we will create mongodb.js file.

 

 

 

 

 

 
Now we will write code in index.js for importing mongodb client and some code.


1. Importing MongoDB and Setting Up Connection:


const { MongoClient } = require('mongodb');
const url = 'mongodb://127.0.0.1:27017';


Here, you are importing the MongoClient class from the 'mongodb' package, which is the official MongoDB driver for Node.js. You define the connection URL for your MongoDB server. In this case, it's mongodb://127.0.0.1:27017, which is the default address and port for a locally running MongoDB server.



2. Defining Database and Creating a MongoClient:


const databaseName = 'e-comm';
const client = new MongoClient(url);



You specify the name of the database you want to connect to (e-comm), and then you create a new instance of the MongoClient using the provided connection URL.





3. Asynchronous Function to Retrieve Data:



async function dbConnect() {
  let result = await client.connect();
  let db = result.db(databaseName);
  return db.collection("products")
 
}



# This function, getData, is marked as async, indicating that it contains asynchronous operations.

# await client.connect();: It connects to the MongoDB server asynchronously and returns a result. This result is an instance of the MongoClient connected to the MongoDB server.

# let db = result.db(databaseName);: It retrieves the specified database (e-comm in this case) from the connected MongoClient.

# let collection = db.collection('products');: It gets a reference to the 'products' collection within the 'e-comm' database.


4. exports the dbConnect:


module.exports = dbConnect;


The module concludes by exporting the dbConnect. When executed, it will connect to the MongoDB server, retrieve data from the 'products' collection, and log the result to the console.

 

Whole Code (/mongodb/mongodb)

 

 

const { MongoClient } = require('mongodb');
const uri = 'mongodb://127.0.0.1:27017/';
const client = new MongoClient(uri);
const dbName = 'e-comm';

async function dbConnect()
{
    //handle promises
    let result = await client.connect();
    console.log(result)
    db = result.db(dbName);  
    return db.collection("products")
}

module.exports = dbConnect;

 

 

Now we will write the code in index.js file for read the data from mongodb.

const dbConnect = require('./mongodb/mongodb')


const main = async () => {
  let data = await dbConnect();
  data = await data.find({}).toArray();
  console.log(data)
}

main();

 

 

Here we first import by const dbConnect with require('./mongodb/mongodb') and promises handle with async and await.

If you want more information about async and await - CLICK HERE

 

 

 

 

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