How to Create a Database in MongoDB: A Quick Guide

So, you've identified MongoDB as the best database choice for your application, but aren't quite sure how to get your database up and running. You've come to the right place, and the good news is that it takes less than a minute.

The assumption here is that you already have a MongoDB Atlas, MongoDB Community Edition, or MongoDB Enterprise Edition cluster deployed.

For the sake of this example, the MongoDB Shell will be used, but everything will translate to other tools and programming languages with minimal differences.

After connecting to your cluster, you could execute something like this:

use("dbinc");

In the above example, "dbinc" is the database we want to use. However, the use function only changes the context. It doesn't actually create a database. 

Unlike other database tools, MongoDB only creates a database when storing data. This could be when you create a collection or your first document.

Take the following, for example:

use("dbinc");

db.createCollection("employees");

The above commands would create a "dbinc" database with an "employees" collection. It should be called out though that you don't need to explicitly create a collection prior to creating documents. 

You can verify that the database was created by executing the following command:

show dbs

To change things up, take the following, for example:

use("dbinc");

db.employees.insertMany([
    { "name": "Nic Raboy", "title": "Master of Shenanigans", "salary": 50000, "last_raise_date": new Date("2013-06-01") },
    { "name": "Megan Grant", "title": "Word Wrangler", "salary": 125000, "last_raise_date": new Date("2020-12-01") },
    { "name": "Tony Kim", "title": "Alliance Czar", "salary": 80000, "last_raise_date": new Date("2025-02-01") },
]);

In the above example, "dbinc" is our database and "employees" is our collection, but if neither exists, both will be created when we insert our data. If either of the two already exists, that is fine too. We'll just be adding our new documents to them.

While out of the scope of this particular article, it is worth noting that MongoDB will create an _id value for you if one isn’t specified. There’s no need to worry about primary key definitions.

There are a few common pitfalls that you should look out for when working with databases in MongoDB.

• Don’t assume that use(“db_name”) will create a database because it won’t. Remember, you have to create a collection or add data first.
• If you have a typo in your database name or collection name, you won’t get a warning. Instead, a new database or collection might be created, just like in the previous example.
• Pay attention to the case sensitivity in the database and collection name.

If you avoid the common pitfalls above, creating and working with databases in MongoDB should be a breeze.

Conclusion

Creating databases in MongoDB is not a difficult task and is not something you need to worry about prior to working with your data, since databases in MongoDB are only created when collections—or in most cases, documents—are created.

Need a more thorough example with more tooling? Get all the details about how to create a MongoDB database in the MongoDB blog.

If you’re in data science or a similar role, check out the Introduction to MongoDB in Python course.