Creating a Database using mongosh

Creating a Database using mongosh

Introduction

MongoDB Shell (mongosh) is an interactive JavaScript interface to MongoDB. It allows you to interact with your databases, collections, and documents. In this tutorial, we will cover how to create a database using mongosh.

Prerequisites

• MongoDB installed on your machine.

• Access to mongosh. If you installed MongoDB correctly, mongosh should be available in your command line.

Step 1: Start mongosh

1. Open Terminal/Command Prompt:

   • Launch your terminal (macOS/Linux) or command prompt (Windows).

2. Start mongosh:

   • Type the following command and press Enter:

     mongosh

   • You should see a welcome message and the mongosh prompt:

     Current Mongosh Log ID: ...
     Connecting to: mongodb://localhost:27017

   • This indicates that you are connected to your MongoDB instance.

Step 2: Create a Database

In MongoDB, a database is created when you first store data in it. However, you can explicitly switch to a new database using the use command. Here's how:

1. Use the use Command:

   • To create a new database (for example, myNewDatabase), type the following command:

     use myNewDatabase

   • After executing this command, you will see a message like:

     switched to db myNewDatabase

   • This indicates that you've switched to myNewDatabase, but it won’t actually exist until you create at least one collection within it.

Step 3: Create a Collection

Collections in MongoDB are equivalent to tables in relational databases. To create a collection and thus confirm the existence of the database, you can insert a document.

1. Create a Collection and Insert a Document:

   • Let’s create a collection named users and insert a document:

     db.users.insertOne({ name: "Pankaj", age: 30, city: "Indore" })

   • This command does two things:

     • It creates a collection called users.

     • It inserts a document containing the user's details.

2. Check the Database:

   • To see the databases available, use the following command:

     show dbs

   • You should now see myNewDatabase in the list, provided it contains data.

Step 4: Verify the Collection

1. Show Collections:

   • To verify that the users collection was created, use:

     show collections

   • You should see users listed as a collection in myNewDatabase.

2. Find Documents in the Collection:

   • To view the documents within the users collection, run:

     db.users.find()

   • This command will display all documents in the users collection. You should see something like this:

     { "_id": ObjectId("..."), "name": "Pankaj", "age": 30, "city": "Indore" }

Step 5: Additional Operations

Creating More Collections

You can create additional collections in the same database. For example, create a products collection:

db.products.insertOne({ productName: "Laptop", price: 50000 })

Viewing All Databases

To view all databases you have created, you can run:

show dbs

Dropping a Database

If you want to delete a database, you can do so by first switching to it and then dropping it:

use myNewDatabase
db.dropDatabase()

Conclusion

You have successfully created a database using mongosh, created collections, and inserted documents. This process is fundamental for working with MongoDB. In future tutorials, we will explore more complex operations such as querying, updating, and deleting documents.

Feel free to reach out with any questions or for further guidance!

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