Jassif Team Institution

let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  let dbo = db.db("mydb");
  dbo.collection("customers").findOne({}, function(err, result) {
    if (err) throw err;
    console.log(result.name);
    db.close();
  });
});

C:\Users\Your Name>node demo_mongodb_findone.js

Company Inc.

let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  let dbo = db.db("mydb");
  dbo.collection("customers").find({}).toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
    db.close();
  });
});

C:\Users\Your Name>node demo_mongodb_find.js

[
  { _id: 58fdbf5c0ef8a50b4cdd9a84 , name: 'John', address: 'Highway 71'},
  { _id: 58fdbf5c0ef8a50b4cdd9a85 , name: 'Peter', address: 'Lowstreet 4'},
  { _id: 58fdbf5c0ef8a50b4cdd9a86 , name: 'Amy', address: 'Apple st 652'},
  { _id: 58fdbf5c0ef8a50b4cdd9a87 , name: 'Hannah', address: 'Mountain 21'},
  { _id: 58fdbf5c0ef8a50b4cdd9a88 , name: 'Michael', address: 'Valley 345'},
  { _id: 58fdbf5c0ef8a50b4cdd9a89 , name: 'Sandy', address: 'Ocean blvd 2'},
  { _id: 58fdbf5c0ef8a50b4cdd9a8a , name: 'Betty', address: 'Green Grass 1'},
  { _id: 58fdbf5c0ef8a50b4cdd9a8b , name: 'Richard', address: 'Sky st 331'},
  { _id: 58fdbf5c0ef8a50b4cdd9a8c , name: 'Susan', address: 'One way 98'},
  { _id: 58fdbf5c0ef8a50b4cdd9a8d , name: 'Vicky', address: 'Yellow Garden 2'},
  { _id: 58fdbf5c0ef8a50b4cdd9a8e , name: 'Ben', address: 'Park Lane 38'},
  { _id: 58fdbf5c0ef8a50b4cdd9a8f , name: 'William', address: 'Central st 954'},
  { _id: 58fdbf5c0ef8a50b4cdd9a90 , name: 'Chuck', address: 'Main Road 989'},
  { _id: 58fdbf5c0ef8a50b4cdd9a91 , name: 'Viola', address: 'Sideway 1633'}
]

let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  let dbo = db.db("mydb");
  dbo.collection("customers").find({}, { projection: { _id: 0, name: 1, address: 1 } }).toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
    db.close();
  });
});

C:\Users\Your Name>node demo_mongodb_find_fields.js

[
  { name: 'John', address: 'Highway 71'},
  { name: 'Peter', address: 'Lowstreet 4'},
  { name: 'Amy', address: 'Apple st 652'},
  { name: 'Hannah', address: 'Mountain 21'},
  { name: 'Michael', address: 'Valley 345'},
  { name: 'Sandy', address: 'Ocean blvd 2'},
  { name: 'Betty', address: 'Green Grass 1'},
  { name: 'Richard', address: 'Sky st 331'},
  { name: 'Susan', address: 'One way 98'},
  { name: 'Vicky', address: 'Yellow Garden 2'},
  { name: 'Ben', address: 'Park Lane 38'},
  { name: 'William', address: 'Central st 954'},
  { name: 'Chuck', address: 'Main Road 989'},
  { name: 'Viola', address: 'Sideway 1633'}
]

let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  let dbo = db.db("mydb");
  dbo.collection("customers").find({}, { projection: { address: 0 } }).toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
    db.close();
  });
});

let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  let dbo = db.db("mydb");
  dbo.collection("customers").find({}, { projection: { _id: 0, name: 1 } }).toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
    db.close();
  });
});

let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  let dbo = db.db("mydb");
  dbo.collection("customers").find({}, { projection: { _id: 0 } }).toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
    db.close();
  });
});

let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  let dbo = db.db("mydb");
  dbo.collection("customers").find({}, { projection: { name: 1, address: 0 } }).toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
    db.close();
  });
});

console.log(result[2].address);

Apple st 652

const { MongoClient } = require('mongodb');

async function findDocuments() {
  const uri = "mongodb://localhost:27017/";
  const client = new MongoClient(uri);

  try {
    await client.connect();
    const database = client.db("mydb");
    const collection = database.collection("customers");
    
    // Find first document
    const firstDoc = await collection.findOne({});
    console.log("First document:", firstDoc);
    
    // Find all documents
    const allDocs = await collection.find({}).toArray();
    console.log("All documents:", allDocs.length);
    
    // Find with projection
    const projectedDocs = await collection.find({}, {
      projection: { _id: 0, name: 1, address: 1 }
    }).toArray();
    console.log("Projected documents:", projectedDocs);
    
  } catch (err) {
    console.error("Error finding documents:", err);
  } finally {
    await client.close();
  }
}

findDocuments();

const { MongoClient } = require('mongodb');

class DataFinder {
  constructor(connectionString, dbName) {
    this.connectionString = connectionString;
    this.dbName = dbName;
    this.client = new MongoClient(connectionString);
  }

  async connect() {
    try {
      await this.client.connect();
      console.log("Connected to MongoDB server");
      this.database = this.client.db(this.dbName);
      return true;
    } catch (error) {
      console.error("Connection failed:", error);
      return false;
    }
  }

  async findFirst(collectionName, query = {}) {
    try {
      const collection = this.database.collection(collectionName);
      const result = await collection.findOne(query);
      return result;
    } catch (error) {
      console.error("Error finding first document:", error);
      throw error;
    }
  }

  async findAll(collectionName, query = {}, projection = {}) {
    try {
      const collection = this.database.collection(collectionName);
      const cursor = collection.find(query, { projection });
      const result = await cursor.toArray();
      return result;
    } catch (error) {
      console.error("Error finding all documents:", error);
      throw error;
    }
  }

  async findWithLimit(collectionName, limit = 10, query = {}, projection = {}) {
    try {
      const collection = this.database.collection(collectionName);
      const cursor = collection.find(query, { projection }).limit(limit);
      const result = await cursor.toArray();
      return result;
    } catch (error) {
      console.error("Error finding with limit:", error);
      throw error;
    }
  }

  async close() {
    try {
      await this.client.close();
      console.log("Connection closed");
    } catch (error) {
      console.error("Error closing connection:", error);
    }
  }
}

// Usage example
async function main() {
  const connectionString = "mongodb://localhost:27017/";
  const dbName = "mydb";
  
  const finder = new DataFinder(connectionString, dbName);

  try {
    const connected = await finder.connect();
    if (!connected) return;

    // Find first document
    const firstCustomer = await finder.findFirst("customers");
    console.log("First customer:", firstCustomer);

    // Find all documents with projection
    const allCustomers = await finder.findAll("customers", {}, { 
      projection: { _id: 0, name: 1, address: 1 } 
    });
    console.log("All customers (projected):", allCustomers);

    // Find with limit
    const limitedCustomers = await finder.findWithLimit("customers", 5);
    console.log("First 5 customers:", limitedCustomers);

    console.log("All find operations completed successfully!");
    
  } catch (error) {
    console.error("Main function error:", error);
  } finally {
    await finder.close();
  }
}

// Run the example
main();