CRUD operations with Prisma in NextJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does CRUD stand for in database operations?

CRUD stands for Create, Read, Update, and Delete. These are the four basic operations to manage data in a database.

beginner

How do you create a new record using Prisma Client in Next.js?

Use the prisma.model.create() method, where model is your database table name. Pass an object with a data property containing the new record's fields.

beginner

Which Prisma Client method is used to fetch multiple records from the database?

The method prisma.model.findMany() fetches multiple records. You can add filters or pagination inside its options.

intermediate

How do you update a record with Prisma Client?

Use prisma.model.update() with two main options: where to specify which record to update, and data to specify the new values.

beginner

What method does Prisma Client provide to delete a record?

Use prisma.model.delete() with a where option to specify the record to remove from the database.

Which Prisma Client method is used to add a new record?

A prisma.model.findUnique()

B prisma.model.delete()

C prisma.model.update()

D prisma.model.create()

The create() method adds a new record to the database.

How do you specify which record to update in Prisma?

A Using the <code>where</code> option

B Using the <code>data</code> option

C Using the <code>select</code> option

D Using the <code>include</code> option

The where option tells Prisma which record to update.

Which method fetches a single record by unique identifier?

A prisma.model.findUnique()

B prisma.model.create()

C prisma.model.findMany()

D prisma.model.delete()

findUnique() fetches one record by a unique field like ID.

What happens if you call prisma.model.delete() without a where clause?

A Deletes all records

B Throws an error

C Deletes the first record

D Updates the record instead

Prisma requires a where clause to know which record to delete; otherwise, it throws an error.

Which of these is NOT a CRUD operation?

A Create

B Read

C Render

D Delete

'Render' is not part of CRUD; CRUD stands for Create, Read, Update, Delete.

Explain how to perform all four CRUD operations using Prisma Client in a Next.js app.

Think about the methods Prisma provides for each operation.

Describe why the 'where' option is important in update and delete operations with Prisma.

Consider what would happen if Prisma didn't know which record to update or delete.

Practice

1. What does the prisma.user.create() method do in Next.js with Prisma?

easy

A. It adds a new user record to the database.

B. It fetches all user records from the database.

C. It updates an existing user record.

D. It deletes a user record from the database.

Solution

1. Step 1: Understand the method name

   The method create() is used to add new data in Prisma.

2. Step 2: Match method to CRUD operation

   Creating means adding new records, so prisma.user.create() adds a new user.

3. Final Answer:

   It adds a new user record to the database. -> Option A

4. Quick Check:

   Create method = Add new record [OK]

Hint: Create method adds new data, not read or delete [OK]

Common Mistakes:

• Confusing create() with findMany() which reads data
• Thinking create() updates existing records
• Assuming create() deletes records

2. Which of the following is the correct syntax to update a user with id 5 using Prisma in Next.js?

easy

A. prisma.user.edit({ where: { id: 5 }, data: { name: 'Alice' } })

B. prisma.user.modify({ id: 5, name: 'Alice' })

C. prisma.user.update({ where: { id: 5 }, data: { name: 'Alice' } })

D. prisma.user.change({ id: 5, data: { name: 'Alice' } })

Solution

1. Step 1: Identify Prisma update syntax

   Prisma uses update() with where and data keys to update records.

2. Step 2: Check option correctness

   Only prisma.user.update({ where: { id: 5 }, data: { name: 'Alice' } }) uses correct method update() and proper keys where and data.

3. Final Answer:

   prisma.user.update({ where: { id: 5 }, data: { name: 'Alice' } }) -> Option C

4. Quick Check:

   Update method uses where and data keys [OK]

Hint: Update uses update({ where, data }) syntax [OK]

Common Mistakes:

• Using non-existent methods like modify(), change(), edit()
• Missing where or data keys in update()
• Passing id directly without where object

3. Given this code snippet in Next.js with Prisma:

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

What will console.log(users.length) output?

medium

A. Always 0, because findMany returns undefined.

B. The total number of users, active or not.

C. An error because findMany needs data key.

D. The number of active users in the database.

Solution

1. Step 1: Understand findMany with where filter

   The findMany() method returns an array of records matching the where condition.

2. Step 2: Analyze the filter condition

   Only users with active: true are returned, so users.length is count of active users.

3. Final Answer:

   The number of active users in the database. -> Option D

4. Quick Check:

   findMany with where returns filtered array [OK]

Hint: findMany returns array; length counts filtered records [OK]

Common Mistakes:

• Thinking findMany returns undefined or error
• Ignoring the where filter effect
• Assuming it returns all users without filter

4. Identify the error in this Prisma delete operation:

await prisma.user.delete({ id: 10 });

medium

A. Missing the 'where' key wrapping the id.

B. Using delete() instead of remove().

C. id should be a string, not a number.

D. delete() cannot be used with await.

Solution

1. Step 1: Check delete() method syntax

   Prisma's delete() requires an object with a where key specifying the record to delete.

2. Step 2: Identify missing where key

   The code passes { id: 10 } directly, missing where: { id: 10 }.

3. Final Answer:

   Missing the 'where' key wrapping the id. -> Option A

4. Quick Check:

   Delete needs where key with id [OK]

Hint: Delete needs where: { id } object, not just id [OK]

Common Mistakes:

• Omitting where key in delete()
• Using remove() which does not exist in Prisma
• Thinking id type must be string always
• Believing delete() can't be awaited

5. You want to update a user's email only if the user exists, otherwise create a new user with that email. Which Prisma method best fits this use case in Next.js?

hard

A. prisma.user.create({ data: { email } })

B. prisma.user.upsert({ where: { email }, update: { email }, create: { email } })

C. prisma.user.update({ where: { email }, data: { email } })

D. prisma.user.findUnique({ where: { email } })

Solution

1. Step 1: Understand the upsert method

   Upsert updates if record exists, else creates new one in Prisma.

2. Step 2: Match use case to method

   Since we want to update or create based on existence, upsert() fits perfectly.

3. Final Answer:

   prisma.user.upsert({ where: { email }, update: { email }, create: { email } }) -> Option B

4. Quick Check:

   Upsert = update or create [OK]

Hint: Use upsert to update or create in one call [OK]

Common Mistakes:

• Using update() alone which fails if user missing
• Using create() alone which fails if user exists
• Using findUnique() which only reads data