CRUD operations with Prisma in NextJS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Prisma create operation in Next.js?

Consider this Next.js API route using Prisma to create a new user:

import { PrismaClient } from '@prisma/client';
const prisma = new PrismaClient();

export default async function handler(req, res) {
  if (req.method === 'POST') {
    const user = await prisma.user.create({
      data: { name: 'Alice', email: '[e-mail]' }
    });
    res.json(user);
  } else {
    res.status(405).end();
  }
}

What will the response JSON contain after a successful POST request?

NextJS

import { PrismaClient } from '@prisma/client';
const prisma = new PrismaClient();

export default async function handler(req, res) {
  if (req.method === 'POST') {
    const user = await prisma.user.create({
      data: { name: 'Alice', email: '[e-mail]' }
    });
    res.json(user);
  } else {
    res.status(405).end();
  }
}

A {"name": "Alice", "email": "[e-mail]"}

B {"error": "Method not allowed"}

C {"id": 1, "name": "Alice", "email": "[e-mail]"}

D {"message": "User created successfully"}

💡 Hint

Prisma returns the full created record including the auto-generated ID.

The prisma.user.create method returns the full user object including the auto-generated id. So the response JSON includes id, name, and email.

❓ state_output

intermediate

What is the result of this Prisma update operation?

Given this Prisma update code snippet in a Next.js API route:

const updatedUser = await prisma.user.update({
  where: { id: 5 },
  data: { email: '[e-mail]' }
});
console.log(updatedUser);

Assuming a user with id = 5 exists, what will console.log(updatedUser) output?

NextJS

const updatedUser = await prisma.user.update({
  where: { id: 5 },
  data: { email: '[e-mail]' }
});
console.log(updatedUser);

A {"id": 5, "name": "Existing Name", "email": "[e-mail]"}

B {"id": 5, "email": "[e-mail]"}

C undefined

D Throws Prisma.PrismaClientKnownRequestError

💡 Hint

The update method returns the full updated record.

The prisma.user.update method returns the entire updated user object, including unchanged fields like name. So the output includes id, name, and the updated email.

🔧 Debug

advanced

Why does this Prisma delete operation cause an error?

Review this Next.js API route snippet:

export default async function handler(req, res) {
  if (req.method === 'DELETE') {
    const deletedUser = await prisma.user.delete({
      where: { email: '[e-mail]' }
    });
    res.json(deletedUser);
  } else {
    res.status(405).end();
  }
}

What error will this code throw if no user has the given email?

NextJS

const deletedUser = await prisma.user.delete({
  where: { email: '[e-mail]' }
});

A No error, returns null

B TypeError: Cannot read property 'email' of undefined

C SyntaxError: Unexpected token delete

D Prisma.PrismaClientKnownRequestError: Record to delete does not exist.

💡 Hint

Deleting a non-existing record causes a specific Prisma error.

Prisma throws PrismaClientKnownRequestError when trying to delete a record that does not exist, indicating the record to delete was not found.

🧠 Conceptual

advanced

Which Prisma query returns all users with emails ending in '.org'?

Choose the Prisma query that correctly fetches all users whose email ends with '.org'.

A prisma.user.findMany({ where: { email: { endsWith: '.org' } } })

B prisma.user.findMany({ where: { email: { contains: '.org' } } })

C prisma.user.findMany({ where: { email: { startsWith: '.org' } } })

D prisma.user.findMany({ where: { email: { equals: '.org' } } })

💡 Hint

Look for the operator that matches the end of a string.

The endsWith operator filters strings that end with the specified substring. contains matches anywhere, startsWith matches the beginning, and equals matches exact strings.

📝 Syntax

expert

What error does this Prisma upsert code produce?

Analyze this Prisma upsert code snippet:

await prisma.user.upsert({
  where: { id: 10 },
  update: { name: 'Bob' },
  create: { email: '[e-mail]' }
});

What error will this code raise?

NextJS

await prisma.user.upsert({
  where: { id: 10 },
  update: { name: 'Bob' },
  create: { email: '[e-mail]' }
});

A SyntaxError: Unexpected token 'await'

B Prisma.PrismaClientValidationError: Missing required field 'name' in create data.

C No error, operation succeeds

D Prisma.PrismaClientKnownRequestError: Unique constraint failed on the fields: (`id`)

💡 Hint

Check if the create data includes all required fields.

The create object is missing the required name field, causing a validation error. Prisma requires all non-nullable fields in create data.