8.2. Inserting documents into MongoDB: Installing MongoDB

To start our journey with MongoDB, it is essential to have the system installed on our machine. So, let's start with the MongoDB installation process.

MongoDB Installation

First, you need to download MongoDB Community Server, which is the free version of MongoDB, directly from the official website. It is important to choose the correct operating system version to ensure compatibility.

After downloading, run the file and follow the installer instructions. During the installation process, an option to install MongoDB as a Windows service will be presented. This is recommended as it allows MongoDB to start automatically when the system starts.

After installation, you need to create a directory to store MongoDB data. By default, MongoDB looks for a directory called '/data/db' in the root directory of your system. You can create this directory using the 'mkdir' command in the terminal.

Finally, to start MongoDB, all you need to do is open a terminal and type 'mongod'. This will start MongoDB and it will begin listening for connections on port 27017.

Inserting Documents into MongoDB

With MongoDB up and running, we can start inserting documents into our database. But first, it is necessary to understand what documents are in the context of MongoDB.

Documents are the equivalent of records or rows in relational databases. In MongoDB, documents are structured as JSON objects, making them very flexible and easy to work with.

To insert documents into MongoDB, we use the 'insert' method. There are two variants of this method: 'insertOne' and 'insertMany'. As the names suggest, 'insertOne' is used to insert a single document, while 'insertMany' is used to insert multiple documents at once.

Here is an example of how to insert a single document into a collection called 'users':

db.users.insertOne({
    name: 'John Doe',
    email: 'johndoe@example.com',
    age: 30
});

This command will insert a document with the fields 'name', 'email' and 'age' into the 'users' collection. If the collection does not exist, it will be created automatically.

To insert multiple documents at once, we can use the 'insertMany' method and provide an array of documents:

db.users.insertMany([
    {
        name: 'Jane Doe',
        email: 'janedoe@example.com',
        age: 28
    },
    {
        name: 'Bob Smith',
        email: 'bobsmith@example.com',
        age: 35
    }
]);

This command will insert two documents into the 'users' collection.

After insertion, MongoDB will return a status report that includes the number of documents inserted and the IDs of those documents.

It is important to note that MongoDB automatically assigns a unique ID to each document at insertion time if one is not provided. This ID is stored in the '_id' field and is used to uniquely identify the document.

In conclusion, inserting documents into MongoDB is a simple and straightforward process, thanks to the flexibility of JSON documents and the powerful insertion methods provided by MongoDB. With these tools in hand, you can start building your MongoDB database with ease.