MongoDB Create Database

MongoDB does not have an explicit CREATE DATABASE command. Instead, a database is automatically created when you insert the first document into a collection. This guide covers how to create a MongoDB database using MongoDB Shell, Node.js (Mongoose), and MongoDB Compass.

1. Create a Database Using MongoDB Shell

A. Open MongoDB Shell

Start the MongoDB shell:

mongosh

B. Switch to the New Database

Even if the database doesn't exist yet, you can switch to it:

use blogDB

✅ Expected Output:

switched to db blogDB

At this point, blogDB exists only in memory but is not saved on disk.

C. Create a Collection (Triggers Database Creation)

To persist the database, insert a document into a new collection:

db.posts.insertOne({ title: "Hello World", content: "This is my first post!" })

✅ Expected Output:

{ "acknowledged": true, "insertedId": ObjectId("...") }

Now, blogDB is permanently created.

D. Verify the Database Exists

Run:

show dbs

✅ Expected Output:

admin    0.000GB
config   0.000GB
local    0.000GB
blogDB   0.001GB

Now, blogDB appears in the list of databases.

2. Create a Database Using Node.js (Mongoose)

A. Install Mongoose (If Not Installed)

npm install mongoose

B. Create a Mongoose Schema

Create models/Post.js:

const mongoose = require('mongoose');

const postSchema = new mongoose.Schema({
    title: { type: String, required: true },
    content: { type: String, required: true },
    createdAt: { type: Date, default: Date.now }
});

const Post = mongoose.model("Post", postSchema);

module.exports = Post;

C. Insert Data to Create the Database

Create createDatabase.js:

const mongoose = require('mongoose');
const Post = require('./models/Post');

mongoose.connect('mongodb://127.0.0.1:27017/blogDB', {
    useNewUrlParser: true,
    useUnifiedTopology: true
}).then(() => console.log("✅ Connected to MongoDB"))
  .catch(err => console.error("❌ Connection Error:", err));

async function createDatabase() {
    try {
        const newPost = new Post({ title: "First Post", content: "This is my first blog post." });
        await newPost.save();
        console.log("✅ Database 'blogDB' created with initial document.");
    } catch (error) {
        console.log("❌ Error creating database:", error.message);
    } finally {
        mongoose.connection.close();
    }
}

createDatabase();

D. Run the Script

node createDatabase.js

✅ Expected Output:

✅ Connected to MongoDB
✅ Database 'blogDB' created with initial document.

3. Create a Database Using MongoDB Compass

If you prefer a graphical interface, follow these steps:

Open MongoDB Compass and connect to your MongoDB server.
Click "Create Database" at the top-left.
Enter Database Name (e.g., blogDB).
Enter Collection Name (e.g., posts).
Click "Create Database".

✅ The database is now created and visible in Compass.

4. Summary

✔ Created a database using MongoDB Shell (use database + insertOne()).
✔ Used Mongoose to create a database programmatically.
✔ Created a database visually using MongoDB Compass.

5. Next Steps

🔹 Set up authentication for secure database access.
🔹 Optimize collections with indexes for better performance.
🔹 Monitor database storage and performance.

Would you like help setting up indexes or authentication? 🚀

Souy Soeng

MongoDB Create Database