Setting up MongoDB Waterline adapter

Summary

1. Install the Adapter:
   Use npm i sails-mongo to install the adapter.

2. Connection String:
   Use the mongodb:// protocol with your host, port, and database name.

3. Adjust Primary Key for MongoDB:
   Update the id property in config/models.js to:

   id: {
     type: 'string',
     columnName: '_id'
   }

4. Debugging:
   Sails provides helpful debugging tips, so always review the error messages for guidance.

5. Testing the Setup:
   Use sails lift to ensure the setup is correct, and test CRUD operations.

6. Compass or Atlas:
   Use MongoDB Compass or Atlas to verify your database records visually.

Transcript

All right, so in this lesson, we're going to look at setting up MongoDB with the sails-mongo adapter. Let's go to the terminal, and here we're going to quickly install the sails-mongo adapter by running:

npm i sails-mongo

This will go to npm and grab the sails-mongo adapter into our demo project. Once that's done, we need to tell Sails about this adapter and how to connect to it using the connection string.

For the adapter, we'll specify sails-mongo. For the URL, we'll modify the connection string pattern slightly because of MongoDB's unique format. Here's how the connection string would look:

mongodb://localhost:27017/demo

• Host: localhost

• Port: The default MongoDB port, 27017

• Database: demo

MongoDB creates the database on the fly, so you don't need to create it manually. It's worth mentioning that these URLs can work for both local and remote databases. For instance, if you're using a hosted database like MongoDB Atlas or services like Heroku or Render, you'd grab the connection string from their respective dashboards, and the process would be the same.

Now, back to the terminal. If we run sails lift, you might notice an error. Sails provides explicit feedback when something goes wrong, which is super helpful. In this case, you might see an error saying the connection string is malformed because it requires the protocol mongodb, not just mongo. Let's go back and fix that to mongodb://.

Once corrected, sails lift should work. However, there's one more thing specific to MongoDB: Sails will warn that the default primary key attribute id is not set correctly. For MongoDB, primary keys must have columnName: '_id'.

To fix this, go to config/models.js and adjust the id property:

id: {
  type: 'string',
  columnName: '_id'
}

MongoDB uses an ObjectID for its _id field, which is a unique string, not a number. After making this change, lift Sails again, and everything should work without any errors.

At this point, your connection is good. One way to confirm this is by testing Sails' behavior. For instance, you can create a record in your model:

await User.create({ name: 'Demo User' });

With MongoDB, you'll notice the id is now a string (the ObjectID) instead of an auto-incremented number, as seen in relational databases.

To verify further, you can use MongoDB Compass or another database client. Connect to the database with your connection string and inspect the documents. You'll see the values you just created.

This is how you set up MongoDB with Sails using the sails-mongo adapter.