MongoDB is a powerful document-oriented Non-Relational database to store numerous BSON format documents. The developer widely uses it due to its flexibility, scalability, multiple data type support, and ease of use. It comprises many built-in methods to perform simple and even complex tasks related to managing databases, such as creating a database, collecting, and deleting them.
This blog will cover the enlisted topics:
- Overview of “db.createCollection()” Method in MongoDB
- How Does the “db.createCollection()” Work in MongoDB?
- Bonus: Managing a Collection in MongoDB
Overview of “db.createCollection()” Method in MongoDB
In MongoDB, the “db.createCollection()” Method creates a new collection in the database. The collections serve the same purpose as tables do in RDBMS, but they are flexible and can store multiple data types in documents. However, if a collection with the same name already exists, the “db.createCollection()” method will not create a new collection with that name but rather will return a reference to the existing collection.
Let us see the basic syntax of this method:
Here in the above syntax:
- The “Collection_Name” is the name of the collection that needs to be created. It should be a string value and cannot include any special character.
- The “Options” parameters are optional arguments, such as “capped”, “size”, “max”, “autoIndex”, and “indexOptionDefaults” to configure the collection.
How Does the “db.createCollection()” Work in MongoDB?
To see how the “db.createCollection()” method works and creates a new collection in MongoDB, follow the steps mentioned below:
Step 1: Connect to MongoDB Server Using MongoDB Shell
Search and open “Command Prompt” from the Start Menu and type this command to connect to the MongoDB server using MongoDB Shell:
Output
The MongoDB server is connected successfully.
Step 2: Retrieve the Names of Available Databases
To list the names of databases, execute the “show dbs” command as below:
Output
The output returned the names of all databases in the MongoDB server.
Step 3: Switch to a Desired MongoDB Database
The next step is to change the current database with the one where users want to create a new collection:
Output
The output returned the message which says, “already on Linuxhint”.
Step 4: Display the Names of Existing Collections
To list the names of existing collections in the current database, type the command given below:
Output
The output returned the name of the existing collection name.
Step 5: Create a New Collection using the “db.createCollection()” Method
Provide the name of the collection as the argument that users want to create. For instance, the “Linuxhint_collection” is considered as below:
Output
The output depicted an “ok” message.
Step 6: To Verify the Result of “db.createCollection()” Method
To verify whether a new collection is created in the current database or not. Use the below command to list all available collection names:
Output
The output displays that a new collection has been created successfully using the “db.createCollection()” method in MongoDB.
Bonus: Managing a Collection in MongoDB
Let us learn some more related and basic tasks for managing a collection in MongoDB.
Create a Document in a Specified Collection
To create a new document in a collection, utilize the “db.collection.insertOne()” method and provide the field-and-value pairs of data for storage. A command to add a document in the newly created collection is provided below:
Output
The document is successfully inserted into the collection.
View Existing Documents in the Collection
To retrieve the existing documents in a collection, use the below command:
Note: Make sure to replace the collection name accordingly.
Output
The output returned the existing documents in the collection.
Delete a Collection from MongoDB
To delete an existing collection from the MongoDB database, use the drop() method:
The command deletes the “Linuxhint_collection” collection from MongoDB.
Output
The success message appeared after the deletion of the “Linuxhint_collection” collection from the MongoDB Database.
Conclusion
In MongoDB, the “db.createCollection()” method creates a new collection in the current database but only if no already existing collection has the same name. To utilize this method, the user must connect to a MongoDB server and switch to the desired database. After that, create a collection by executing this method. This post has discussed the working of the “db.createCollection()” method in MongoDB.
