Prisma ORM with GraphQL - Mini Project: Build & Apply

Build a Simple Prisma ORM with GraphQL API

📖 Scenario: You are creating a small backend API for a bookstore. The API will allow users to query and add books using GraphQL. The data will be stored using Prisma ORM connected to a database.

🎯 Goal: Build a GraphQL API that uses Prisma ORM to manage a list of books with fields id, title, and author. You will create the Prisma schema, configure the Prisma client, write GraphQL type definitions, and implement resolvers to query and add books.

📋 What You'll Learn

Create a Prisma schema with a Book model having id, title, and author fields

Generate Prisma client from the schema

Set up GraphQL type definitions for Book and queries/mutations

Implement resolvers to fetch all books and add a new book using Prisma client

💡 Why This Matters

🌍 Real World

Building backend APIs for applications that need to manage data with a database and expose it via GraphQL.

💼 Career

Understanding Prisma ORM and GraphQL is valuable for backend developers working with modern JavaScript/TypeScript stacks.

1

Create Prisma schema with Book model

Create a Prisma schema file named schema.prisma with a Book model. The model should have an id field of type Int that is the primary key and auto-increments, a title field of type String, and an author field of type String. Also include a datasource block for SQLite and a generator block for Prisma client.

GraphQL

// Your Prisma schema goes here
// Define datasource, generator, and Book model

Hint

Remember to define the datasource and generator blocks before the model.

2

Generate Prisma client and import it

After creating the Prisma schema, run npx prisma generate to generate the Prisma client. Then, in your GraphQL server file, import PrismaClient from @prisma/client and create a new instance called prisma.

GraphQL

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

// Create a new PrismaClient instance called prisma
// Your code here

Hint

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

3

Define GraphQL type definitions for Book and queries

Define GraphQL type definitions using gql from apollo-server. Create a Book type with id (ID!), title (String!), and author (String!). Define a Query type with a books field that returns a list of Book. Also define a Mutation type with addBook(title: String!, author: String!): Book!.

GraphQL

import { gql } from 'apollo-server';

// Define typeDefs using gql
// Your code here

Hint

Use backticks to define the GraphQL schema string with gql.

4

Implement resolvers to query and add books

Create a resolvers object with a Query field containing a books resolver that returns prisma.book.findMany(). Add a Mutation field with an addBook resolver that takes title and author from args and returns prisma.book.create with the data. Export both typeDefs and resolvers.

GraphQL

// Define resolvers object with Query and Mutation
// Your code here

// Export typeDefs and resolvers

Hint

Resolvers connect GraphQL queries and mutations to Prisma client methods.

Practice

1. What is the main role of Prisma ORM when used with GraphQL?

easy

A. To define GraphQL schema types

B. To style the frontend user interface

C. To handle HTTP requests from clients

D. To manage database access and queries easily

Solution

1. Step 1: Understand Prisma ORM's purpose

   Prisma ORM acts as a tool to simplify database operations by providing an easy way to query and manage data.

2. Step 2: Differentiate Prisma from GraphQL schema and frontend roles

   GraphQL schema defines data types and operations, while frontend styling is unrelated to Prisma's role.

3. Final Answer:

   To manage database access and queries easily -> Option D

4. Quick Check:

   Prisma ORM = database access tool [OK]

Hint: Prisma handles database, GraphQL defines schema [OK]

Common Mistakes:

• Confusing Prisma with GraphQL schema definition
• Thinking Prisma manages frontend UI
• Assuming Prisma handles HTTP requests

2. Which of the following is the correct way to import Prisma Client in a Node.js GraphQL resolver file?

easy

A. import Prisma from 'prisma';

B. const PrismaClient = require('prisma-client');

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

D. const { Prisma } = require('@prisma/client');

Solution

1. Step 1: Recall Prisma Client import syntax

   The official Prisma Client is imported using ES module syntax: import { PrismaClient } from '@prisma/client';

2. Step 2: Identify incorrect import forms

   Options B, C, and D use wrong package names or destructuring that Prisma does not support.

3. Final Answer:

   import { PrismaClient } from '@prisma/client'; -> Option C

4. Quick Check:

   Correct Prisma import = import { PrismaClient } from '@prisma/client'; [OK]

Hint: Use exact package '@prisma/client' with named import [OK]

Common Mistakes:

• Using wrong package name like 'prisma-client'
• Incorrect destructuring of PrismaClient
• Mixing CommonJS require with ES import incorrectly

3. Given this GraphQL resolver using Prisma:

const users = await prisma.user.findMany({ where: { active: true } });
return users;

What does this resolver return?

medium

A. All users including inactive ones

B. Only users with active set to true

C. An error because 'active' is not a valid field

D. An empty list always

Solution

1. Step 1: Analyze the Prisma query filter

   The query uses findMany with a where clause filtering users where active equals true.

2. Step 2: Understand the result of the query

   It returns only users whose active field is true, excluding inactive users.

3. Final Answer:

   Only users with active set to true -> Option B

4. Quick Check:

   findMany with where active:true = filtered users [OK]

Hint: Where filters results; active:true returns only active users [OK]

Common Mistakes:

• Assuming it returns all users ignoring filter
• Thinking it causes an error without schema check
• Believing it always returns empty list

4. You wrote this resolver code but get an error:

const newUser = prisma.user.create({
  data: {
    name: 'Alice'
  }
});
return newUser;

What is the likely cause of the error?

medium

A. Missing await before prisma.user.create call

B. Incorrect field name 'name' in data

C. Using create instead of findMany

D. Returning newUser before defining it

Solution

1. Step 1: Check asynchronous Prisma call

   prisma.user.create returns a Promise, so it needs await to resolve before returning.

2. Step 2: Identify missing await causing error

   Without await, newUser is a Promise, not the created user object, causing issues in return.

3. Final Answer:

   Missing await before prisma.user.create call -> Option A

4. Quick Check:

   Async Prisma calls need await [OK]

Hint: Always await Prisma async calls in resolvers [OK]

Common Mistakes:

• Forgetting to await async Prisma methods
• Assuming create returns data synchronously
• Confusing create with findMany usage

5. You want to fetch a user and their posts in one GraphQL query using Prisma. Which resolver code correctly fetches the user with their posts included?

hard

A. const user = await prisma.user.findUnique({ where: { id }, include: { posts: true } });

B. const user = await prisma.user.findMany({ where: { id }, select: { posts: false } });

C. const user = await prisma.post.findMany({ where: { userId: id } });

D. const user = await prisma.user.findUnique({ where: { id } }); const posts = await prisma.post.findMany({ where: { userId: id } });

Solution

1. Step 1: Understand Prisma's include option

   Using include: { posts: true } fetches related posts along with the user in one query.

2. Step 2: Compare options for fetching user with posts

   const user = await prisma.user.findUnique({ where: { id }, include: { posts: true } }); uses findUnique with include correctly; const user = await prisma.user.findMany({ where: { id }, select: { posts: false } }); excludes posts; const user = await prisma.post.findMany({ where: { userId: id } }); fetches posts only; const user = await prisma.user.findUnique({ where: { id } }); const posts = await prisma.post.findMany({ where: { userId: id } }); fetches separately, not in one query.

3. Final Answer:

   const user = await prisma.user.findUnique({ where: { id }, include: { posts: true } }); -> Option A

4. Quick Check:

   Include fetches relations in one query [OK]

Hint: Use include to fetch related data in one Prisma query [OK]

Common Mistakes:

• Using findMany instead of findUnique for single user
• Not using include to fetch related posts
• Fetching posts separately causing extra queries