19-Nodejs Course 2023: Database Collections

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Database Collections

As we mentioned earlier, the data are stored in collections which is referred as well to Tables, now we want to know how to create or get a collection using Nodejs, it's just as easy as you may think, just call the collection method from the database :)

Users Collection

Open src/app/users/controllers/list-users.ts and update it to the following code

// src/app/users/controllers/list-users.ts
import database from "core/database";

export default async function usersList(request: any) {
  const usersCollection = database.database.collection("users");

  const usersList = await usersCollection.find({}).toArray();

  return {
    users: usersList,
  };
}

Don't forget to async the function

What we did here we called our database class which internally holds the mongodb database driver, then we called collection method and passed to it our collection name which we'll call users.

Now we have an instance of collection, we can use it to perform operations on it, in this case we called find method which returns a cursor, then we called toArray method which returns an array of documents.

You should see now an empty array in the response, because we don't have any users in our database, let's add some users.

Enhancing the collection call

Calling database.database is not a good practice, so let's make it better, open src/core/database/database.ts and update it to the following code

// src/core/database/database.ts
import { Db } from "mongodb";

export class Database {
  /**
   * Database instance
   */
  public database!: Db;

  /**
   * Set database instance
   */
  public setDatabase(database: Db) {
    this.database = database;

    return this;
  }

  /**
   * Get database collection
   */
  public collection(collectionName: string) {
    return this.database.collection(collectionName);
  }
}

const database = new Database();

export default database;

Now we can use the collection method directly from the database instance, open src/app/users/controllers/list-users.ts and update it to the following code

// src/app/users/controllers/list-users.ts

export default async function usersList(request: any) {
  const usersCollection = database.collection("users");

  const usersList = await usersCollection.find({}).toArray();

  return {
    users: usersList,
  };
}

Create New User

Now we want to create a new user, open src/app/users/controllers/create-user.ts and update it to the following code

// src/app/users/controllers/create-user.ts
import database from "core/database";

export default async function createUser(request: any) {
  // we'll use this for now because of the multiple part, but we'll fix it later
  const name = request.body.name.value;
  const email = request.body.email.value;

  const users = database.collection("users");

  const result = await users.insertOne({
    name,
    email,
  });

  return {
    user: {
      id: result.insertedId,
      name,
      email,
    },
  };
}

Don't forget to async the function

Now let's open postman and create a new user by just adding the following body

{
  "name": "Hasan",
  "email": "hassanzohdy@gmail.com"
}

And that's it! you should see now the same email and name with the a generated id.

Conclusion

In this lesson we learned how to create a collection and how to use it to perform operations on it, we also learned how to create a new user and how to get all users.