Readme.md

DE | Crunchbase Database

Introduction

You will build an small application to perform queries to crunchbase database.

Crunchbase is the premier destination for discovering industry trends, investments, and news about hundreds of thousands of companies globally. From startups to Fortune 500s, Crunchbase is recognized as the primary source of company intelligence by millions of users globally.

Quering Crunchbase

Download crunchbase dataset from here

Use mongoimport to import into companies collection in crunchbase database

💡 Check mongoimport documentation if you don't remember how to do it. 💡

First of all perform in MongoShell the following query in order to know how the documents are structured.

db.companies.find({name: "Facebook"}).pretty()

Let's start

Create a new folder for you project.

$ npm init

Now that we have created the project, add the following packagesclear and mongodb

$ npm install --save mongodb
$ npm install --save clear

Create a new file called main.js

const MongoDB = require('mongodb');
const mongoClient = MongoDB.MongoClient;
const clear = require('clear');
const readline = require('readline');
const rl = readline.createInterface({
	input: process.stdin,
	output: process.stdout
});

const url = `mongodb://localhost:27017/crunchbase`

mongoClient.connect(url, (error, db) => {
  if (error) {
    console.log('Error trying to connect to the Database');
    console.log(error);
  } else {
    console.log('Connection established correctly!! 😬');

  }
});

Try it to see if it works.

$ node main.js

Until now we have created the connection with MongoDB Database.

Let's create the mainMenu, copy the following function after mongoClient.connect();

function printMenu(){
	console.log(`
0.- Exit
1.- List by name all companies.
2.- How many companies are there?
3.- How many companies were founded in 2004?
4.- List by name all companies founded in february of 2004.
5.- List by name all companies founded in the summer of 2004 (april to june) sorted by date.
6.- What companies have offices in "Barcelona".
7.- List the 10 companies with more employees sorted ascending (show name and employees).
8.- Find the company with the name "Facebook"
9.- How many employees has Facebook?
10.- List the name of all the products of Facebook
11.- List the people that are working at Facebook right now (check relationships field)
12.- How many people are not working anymore at Facebook
13.- List all the companies where "david-ebersman" has worked.
14.- List by name the competitors of Facebook
15.- Names of the companies that has "social-networking" in tag-list (be aware that the value of field is a string check regex operators)
16.- How many companies that has "social-network" in tag-list and founded between 2002 and 2016 inclusive
17.- Names and locations of companies that have offices in London
18.- How many companies that has "social-network" in tag-list and founded between 2002 and 2016 inclusive and has offices in New York
`);
}

This are all the queries that you have to do.

Now let's create the main function

...
mongoClient.connect(url, (error, db) => {
  if (error) {
    console.log('Error trying to connect to the Database');
    console.log(error);
  } else {
    console.log('Connection established correctly!! 😬');

    function mainMenu(){
      clear();
      printMenu();
      rl.question('Type an option: ', (option) => {
        switch(option){
          case "1":
            console.log('you typed 1');
            rl.question(`\nType enter to continue: `, (answer) => {mainMenu()});
            break;
          case "2":
            console.log('you typed 2');
            rl.question(`\nType enter to continue: `, (answer) => {mainMenu()});
            break;
          case "0":
            console.log(`👋👋👋👋 😞 \n`);
            db.close((error) => { process.exit(0) });
            break;
          default:
            mainMenu();
            break;
        }
      });
	}

    mainMenu();

  }
});

function printMenu(){
...
}

What we did?

We made an infinite loop until the option is 0. This rl object will allow us to ask through the terminal and we will get a callback with the answer. Once we get the answer we make a switch where we will perform the different queries.

Try it to see if it works

$ node main.js

Type an option and if you see the console message, it's a good signal.

Let's build the first query

Inside case "1":

💣 Delete lines inside the case console.log('you typed 1'); and rl.question('\nType enter to continue: ', (answer) => {mainMenu()}); 💣

db.collection('companies').find({}, {name: 1, _id: 0}).toArray((error, result) => {
  if (error) {
    console.log(error);
    rl.question(`\nType enter to continue: `, (answer) => { mainMenu() });
  } else {
    console.log(result);
    rl.question(`\nType enter to continue: `, (answer) => { mainMenu() });
  }
})

Now it's your turn

Perfom the 17 queries, following the instructions how we did before

Extra Queries

If you feel motivated you can do 3 more extra queries.

• Find all the distinct categories, so list all unique categories use distinct method

• How many companies mention Google in their overview.

💣 In order to perform this query you have to create an index execute the following db.companies.createIndex({overview: "text"}) in MongoShell 💣

💡 For the query check text search operator 💡

• Find companies founded in 2004 and having 5 or more rounds of funding, calculate the average amount raised.

💡 Use Framework aggregation 💡

Summary

In this exercise you practice with MongoDB Driver to perform different queries.

Extra Resources

MongoDB NodeJS Driver Documentatio

MongoShell Documentation