CRUD with Prisma in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does CRUD stand for in software development?

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

beginner

How does Prisma help in a NestJS application?

Prisma is an ORM (Object-Relational Mapping) tool that helps NestJS apps interact with databases easily by providing a type-safe and auto-generated query builder.

beginner

In Prisma, what is the purpose of the Prisma Client?

Prisma Client is an auto-generated library that lets you perform database operations like create, read, update, and delete with simple JavaScript/TypeScript methods.

intermediate

What is the typical structure of a CRUD service method in NestJS using Prisma?

A CRUD service method calls Prisma Client methods like create(), findMany(), update(), or delete() to perform database operations, usually wrapped in async functions.

beginner

Why should you use async/await with Prisma in NestJS?

Database operations are asynchronous. Using async/await ensures your code waits for the database response before continuing, preventing errors and making code easier to read.

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

A delete()

B findMany()

C update()

D create()

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

What does the findMany() method do in Prisma?

A Finds and returns multiple records

B Updates multiple records

C Deletes multiple records

D Creates multiple records

findMany() retrieves multiple records from the database.

In NestJS, where do you usually call Prisma Client methods for CRUD operations?

A In the controller

B In the service

C In the module

D In the main.ts file

CRUD operations are typically handled in the service layer.

Which keyword is used to handle asynchronous Prisma calls in NestJS?

A await

B asyncify

C wait

D sync

The await keyword is used to wait for asynchronous Prisma calls.

What is the main benefit of using Prisma with NestJS?

A It automatically creates UI components

B It replaces the need for controllers

C It simplifies database access with type safety

D It manages server deployment

Prisma simplifies database access and provides type safety.

Explain how you would implement a 'Read' operation using Prisma in a NestJS service.

Think about how to get data from the database safely and asynchronously.

Describe the steps to create a new record in the database using Prisma within a NestJS app.

Focus on how to add data and handle the response.

Practice

1. In NestJS with Prisma, which method is used to retrieve multiple records from the database?

easy

A. create

B. update

C. findMany

D. delete

Solution

1. Step 1: Understand Prisma CRUD methods

   Prisma provides create to add, findMany to get multiple records, update to change, and delete to remove records.

2. Step 2: Identify method for retrieving multiple records

   The method findMany is specifically designed to fetch many records from the database.

3. Final Answer:

   findMany -> Option C

4. Quick Check:

   Retrieve multiple records = findMany [OK]

Hint: Remember: findMany fetches many records [OK]

Common Mistakes:

• Confusing create with findMany
• Using update to retrieve data
• Trying to delete to get records

2. Which of the following is the correct syntax to create a new user record using Prisma in a NestJS service?

easy

A. this.prisma.user.create({ data: { name: 'Alice' } })

B. this.prisma.user.findMany({ data: { name: 'Alice' } })

C. this.prisma.user.update({ data: { name: 'Alice' } })

D. this.prisma.user.delete({ data: { name: 'Alice' } })

Solution

1. Step 1: Identify the method to add a record

   The create method is used to add new records in Prisma.

2. Step 2: Check the syntax for creating a user

   The correct syntax is this.prisma.user.create({ data: { ... } }) where data holds the new record's fields.

3. Final Answer:

   this.prisma.user.create({ data: { name: 'Alice' } }) -> Option A

4. Quick Check:

   Create new record = create method [OK]

Hint: Use create with data object to add records [OK]

Common Mistakes:

• Using findMany instead of create
• Passing data to update without where clause
• Using delete method to add records

3. Given this Prisma update call in a NestJS service:

this.prisma.user.update({ where: { id: 5 }, data: { email: '[e-mail]' } })

What will this operation do?

medium

A. Delete the user with id 5

B. Update the email of the user with id 5 to '[e-mail]'

C. Create a new user with id 5 and email '[e-mail]'

D. Return all users with email '[e-mail]'

Solution

1. Step 1: Understand the update method parameters

   The update method requires a where clause to find the record and data to specify changes.

2. Step 2: Analyze the given call

   It targets user with id: 5 and changes the email field to '[e-mail]'.

3. Final Answer:

   Update the email of the user with id 5 to '[e-mail]' -> Option B

4. Quick Check:

   Update with where and data changes record [OK]

Hint: Update needs where to find record, data to change [OK]

Common Mistakes:

• Thinking update creates new records
• Confusing update with delete
• Missing where clause causes errors

4. What is wrong with this Prisma delete call in a NestJS service?

this.prisma.user.delete({ data: { id: 3 } })

medium

A. The delete method should use a where clause, not data

B. The delete method cannot delete by id

C. The syntax is correct and will delete user with id 3

D. The delete method requires an update object

Solution

1. Step 1: Check Prisma delete method syntax

   The delete method requires a where clause to specify which record to remove.

2. Step 2: Identify the error in the code

   The code incorrectly uses data instead of where, causing a syntax error.

3. Final Answer:

   The delete method should use a where clause, not data -> Option A

4. Quick Check:

   Delete needs where, not data [OK]

Hint: Delete uses where to find record, not data [OK]

Common Mistakes:

• Using data instead of where in delete
• Trying to update in delete method
• Omitting where clause causes errors

5. You want to update a user's name only if the user exists, otherwise create a new user with that name using Prisma in NestJS. Which approach correctly handles this logic?

hard

A. Use delete then create to replace the user

B. Call update and if it fails, call create manually

C. Use findMany then create without update

D. Use upsert with where, update, and create objects

Solution

1. Step 1: Understand Prisma's upsert method

   The upsert method updates a record if it exists or creates it if not, combining both actions safely.

2. Step 2: Identify correct usage for conditional update or create

   Using upsert with where to find the user, update for changes, and create for new record is the best practice.

3. Final Answer:

   Use upsert with where, update, and create objects -> Option D

4. Quick Check:

   Conditional update or create = upsert [OK]

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

Common Mistakes:

• Manually catching update errors to create
• Using findMany without update
• Deleting before creating wastes operations