Connection

This guide explains how to connect to your MongoDB database using Monarch ORM. Proper database connection setup is essential for your application to interact with your data.

Core Concepts

Monarch ORM uses the official MongoDB Node.js driver under the hood. You'll need to use the createClient and createDatabase functions to establish and manage the connection.

Connecting to MongoDB

1. Import the necessary modules

import { createClient, createDatabase } from "monarch-orm";
import { createSchema, string } from "monarch-orm";
 
const UserSchema = createSchema("users", {
  name: string(),
});

2. Establish the MongoDB Client

Use the createClient function to establish a connection to your MongoDB server.

const client = createClient("mongodb://localhost:27017/your-db-name"); // Replace with your MongoDB URI

Explanation:

• createClient(uri: string, options?: MongoClientOptions): Creates a new MongoClient instance.
  • uri (required): The MongoDB connection string (URI). This specifies the location of your MongoDB server and any authentication credentials.
  • options (optional): An object containing additional options for the MongoDB client (e.g., connection pooling settings, authentication options). See the MongoDB Node.js driver documentation for a full list of available options.

Example Connection URIs:

• Local MongoDB: "mongodb://localhost:27017/your-db-name"
• MongoDB Atlas (with username/password): "mongodb+srv://username:password@cluster-url/your-db-name?retryWrites=true&w=majority"
• Authentication Required (Local): "mongodb://username:password@localhost:27017/your-db-name"

3. Create the Database Instance

Use the createDatabase function to create a database instance and associate your schemas with it.

const { collections } = createDatabase(client.db(), {
  users: UserSchema, // Pass your schemas here
});

Explanation:

• createDatabase(db: Db, schemas: object): Creates a database instance and associates it with specified schemas.
  • db (required): Instance of the MongoDB client's db you wish to use
  • schemas (required): An object where the keys are names for your collections and the values are schema definitions.

4. Closing the Connection

It's crucial to close the MongoDB connection when your application is finished using it to release resources.

async function main() {
  // ... your application logic ...
  await client.close();
}

Complete Example

import { createClient, createDatabase, createSchema, string } from "monarch-orm";
 
const UserSchema = createSchema("users", {
  name: string(),
});
 
const client = createClient("mongodb://localhost:27017/your-db-name"); // Replace with your MongoDB URI
 
async function main() {
  try {
    await client.connect();  // Explicitly connect
 
    const { collections } = createDatabase(client.db(), {
      users: UserSchema,
    });
 
    // Perform database operations...
    const newUser = await collections.users.insertOne({ name: "Alice" }).exec();
    console.log("Inserted User:", newUser);
 
  } catch (error) {
    console.error("Error connecting to MongoDB:", error);
  } finally {
    await client.close();
    console.log("MongoDB connection closed.");
  }
}
 
main();

Connection Options (MongoClientOptions)

The createClient function accepts an optional MongoClientOptions object to configure the connection. Some commonly used options include:

• useNewUrlParser: (Deprecated - true by default in newer MongoDB drivers) Enables the new URL parser.
• useUnifiedTopology: Enables the new unified topology layer. Generally recommended.
• serverSelectionTimeoutMS: Specifies the timeout (in milliseconds) for selecting a server.
• heartbeatFrequencyMS: Specifies the frequency (in milliseconds) at which the driver sends heartbeats to the server.
• poolSize: Specifies the maximum number of connections in the connection pool.
• autoReconnect: (Deprecated) Enable or disable auto reconnection.

Refer to the official MongoDB Node.js driver documentation for a comprehensive list of available options: [https://www.mongodb.com/docs/drivers/node/current/api/mongo