NodeJs with SQL Server Functions

Back to: Mastering Node.js and SQL Server

In this lesson, we’ll explore how to work with SQL Server functions in a Node.js application. We’ll cover the basics of setting up your development environment, connecting to a SQL Server database, and executing SQL Server functions. Throughout this lesson, we’ll provide code examples to illustrate each step.

Prerequisites

Before you begin, ensure you have the following prerequisites in place:

  1. Node.js and npm: Install Node.js from the official website if you haven’t already (https://nodejs.org/). npm, the Node Package Manager, comes bundled with Node.js.
  2. SQL Server: Have access to a SQL Server database instance. You can use Microsoft SQL Server or SQL Server Express, depending on your needs.
  3. SQL Server Functions: Create one or more SQL Server functions in your database. For this lesson, we’ll use a simple scalar function as an example.

Step 1: Set Up Your Node.js Project

Start by creating a new directory for your Node.js project and navigating to it in your terminal.

mkdir node-sql-server-functions
cd node-sql-server-functions

Initialize your Node.js project by running:

npm init -y

This command will create a package.json file with default settings.

Step 2: Install Dependencies

To interact with SQL Server from your Node.js application, you’ll need the mssql package. Install it using npm:

npm install mssql

Step 3: Create a Node.js Script

In your project directory, create a JavaScript file, e.g., app.js, to write your Node.js code.

// Import the 'mssql' module
const sql = require('mssql');

// Configure the database connection
const config = {
  user: 'your_username',
  password: 'your_password',
  server: 'localhost', // Change this to your SQL Server instance
  database: 'your_database_name',
};

// Create a function to execute the SQL Server function
async function executeSqlServerFunction() {
  try {
    // Connect to the SQL Server database
    await sql.connect(config);

    // Define the SQL query that calls your SQL Server function
    const query = 'SELECT dbo.MyScalarFunction() AS Result';

    // Execute the query
    const result = await sql.query(query);

    // Print the result
    console.log('SQL Server Function Result:', result.recordset[0].Result);
  } catch (err) {
    console.error('Error:', err);
  } finally {
    // Close the database connection
    sql.close();
  }
}

// Call the function to execute the SQL Server function
executeSqlServerFunction();

In the code above:

  • We import the mssql module and configure the database connection with your credentials and database information.
  • We create an asynchronous function executeSqlServerFunction() to connect to the database, execute the SQL query, and print the result.
  • Inside the function, we define the SQL query that calls your SQL Server function (dbo.MyScalarFunction() in this example).
  • Finally, we call the function to execute the SQL Server function and log the result.

Step 4: Run Your Node.js Script

Save your app.js file and run your Node.js script using the following command:

node app.js

Your script will connect to the SQL Server database, execute the SQL Server function, and display the result in the console.

Conclusion

In this lesson, you’ve learned how to set up a Node.js project, install the necessary dependencies, and execute SQL Server functions using the mssql package. This is just the beginning of what you can achieve with Node.js and SQL Server integration. You can now build more complex applications that interact with your SQL Server database using functions for data manipulation, aggregation, and more.