Database migrations in NextJS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

Understanding migration effect on Next.js app

You have a Next.js app using Prisma for database migrations. After running prisma migrate dev, what happens to your database schema?

A The Prisma schema file is overwritten with the current database schema.

B The database schema resets to an empty state, deleting all data.

C Nothing changes until you restart the Next.js server.

D The database schema updates to match the Prisma schema, and a new migration file is created.

💡 Hint

Think about what prisma migrate dev does to keep your database and Prisma schema in sync.

Running prisma migrate dev updates your database schema to match your Prisma schema and creates a migration file to track changes.

📝 Syntax

intermediate

Identify the correct migration script syntax

Which of the following Prisma migration schema snippets correctly adds a new email field to a User model?

A model User { id Int @id @default(autoincrement()) email String? }

B model User { id Int @id @default(autoincrement()) email Boolean }

C model User { id Int @id @default(autoincrement()) email String }

D model User { id Int @id @default(autoincrement()) email Int }

💡 Hint

Consider the data type for an email address and whether it should be optional.

The email field should be a required String type to store email addresses correctly.

🔧 Debug

advanced

Fix migration error due to conflicting schema changes

You run prisma migrate dev but get an error about conflicting migrations. What is the likely cause?

A You have two migration files that change the same table in incompatible ways.

B Your Prisma client is outdated and needs to be reinstalled.

C You forgot to restart the Next.js server after schema changes.

D Your database connection string is missing in the .env file.

💡 Hint

Think about what happens when multiple migrations try to change the same part of the database.

Conflicting migrations occur when two migration files try to modify the same table or column in incompatible ways, causing errors.

❓ state_output

advanced

Result of migration rollback in Next.js Prisma setup

After applying several migrations, you run prisma migrate reset. What is the state of your database?

A Only the last migration is undone, keeping previous migrations intact.

B The database is dropped, recreated, and all migrations are reapplied from scratch.

C The database schema stays the same but all data is deleted.

D Nothing happens unless you manually delete migration files.

💡 Hint

Consider what prisma migrate reset does to the database and migrations.

This command drops the database, recreates it, and reapplies all migrations to start fresh.

🧠 Conceptual

expert

Choosing migration strategy for production Next.js app

You want to deploy a Next.js app with Prisma to production. Which migration strategy ensures safe schema updates without data loss?

A Use <code>prisma migrate deploy</code> to apply tested migration files without resetting the database.

B Run <code>prisma migrate reset</code> on production to ensure a clean schema.

C Manually edit the database schema and skip Prisma migrations.

D Delete all migration files and generate new ones on production.

💡 Hint

Think about how to safely update a live database without losing data.

prisma migrate deploy applies existing migration files safely in production without resetting or losing data.