Why Prisma offers type-safe database access in NestJS - See It in Action

Why Prisma offers type-safe database access

📖 Scenario: You are building a simple NestJS backend that connects to a database using Prisma. You want to see how Prisma helps you write code that is safe and avoids mistakes by using types.

🎯 Goal: Build a small NestJS service that uses Prisma Client to fetch users from the database with type safety.

📋 What You'll Learn

Create a Prisma Client instance

Define a configuration variable for the user ID to fetch

Write a function that fetches a user by ID using Prisma Client

Return the fetched user in the service method

💡 Why This Matters

🌍 Real World

Backend developers use Prisma with NestJS to safely query databases without runtime errors from wrong field names or types.

💼 Career

Understanding Prisma's type-safe access helps developers write reliable, maintainable backend code that integrates well with TypeScript and NestJS.

1

Create Prisma Client instance

Create a constant called prisma and set it to a new instance of PrismaClient imported from @prisma/client.

NestJS

# Your code here

Need a hint?

Use import { PrismaClient } from '@prisma/client' and then const prisma = new PrismaClient().

2

Add user ID configuration

Create a constant called userId and set it to the number 1 to represent the user ID you want to fetch.

NestJS

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

# Your code here

Need a hint?

Just create const userId = 1.

3

Write function to fetch user by ID

Write an async function called getUserById that takes a parameter id of type number. Inside, use prisma.user.findUnique with where: { id } to fetch the user. Return the result.

NestJS

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

const userId = 1;

# Your code here

Need a hint?

Use async function getUserById(id: number) and inside return await prisma.user.findUnique({ where: { id } }).

4

Call function and export result

Create an async function called main that calls getUserById with userId and stores the result in user. Export main as the default export.

NestJS

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

const userId = 1;

async function getUserById(id: number) {
  return await prisma.user.findUnique({
    where: { id }
  });
}

# Your code here

Need a hint?

Define async function main(), call getUserById(userId), store in user, then return user. Export main as default.