CRUD with Prisma in NestJS - Performance & Optimization

Performance: CRUD with Prisma

MEDIUM IMPACT

This concept affects server response time and database query efficiency, impacting how fast the page can load or update data.

Fetching all records with Prisma in a NestJS app

NestJS

async findAll(page = 1, limit = 10) {
  return await this.prisma.user.findMany({
    skip: (page - 1) * limit,
    take: limit
  });
}

Limits data fetched per request, reducing server load and response time.

📈 Performance GainFaster response, lower memory use, better LCP

Fetching all records with Prisma in a NestJS app

NestJS

async findAll() {
  return await this.prisma.user.findMany();
}

Fetching all records without pagination can cause large data loads, increasing response time and memory use.

📉 Performance CostBlocks server response longer as data size grows, increasing LCP delay

Performance Comparison

Pattern	Database Queries	Server Response Time	Network Payload	Verdict
Fetch all without pagination	1 large query	High due to large data	Large JSON payload	[X] Bad
Fetch with pagination	1 small query	Low and predictable	Small JSON payload	[OK] Good
Update with read then update	2 queries	Higher latency	Minimal payload	[X] Bad
Update with single query	1 query	Lower latency	Minimal payload	[OK] Good
Delete with read then delete	2 queries	Higher latency	Minimal payload	[X] Bad
Delete with single query	1 query	Lower latency	Minimal payload	[OK] Good

Rendering Pipeline

Prisma CRUD operations run on the server before the page renders. Slow queries delay server response, which delays the browser receiving data to paint the page.

→Server Processing

→Network Transfer

→Browser Rendering

⚠️ BottleneckServer Processing due to database query time

Core Web Vital Affected

LCP

This concept affects server response time and database query efficiency, impacting how fast the page can load or update data.

Optimization Tips

1Limit data fetched with pagination to reduce server load and network payload.

2Use single queries for update and delete to minimize database round trips.

3Avoid fetching unnecessary data to improve server response and page load speed.

Performance Quiz - 3 Questions

What is a performance downside of fetching all records without pagination in Prisma?

A It reduces server response time by fetching all data at once.

B It can cause large data loads, increasing server response time and slowing page load.

C It decreases network payload size.

D It improves browser rendering speed.

DevTools: Network

How to check: Open DevTools, go to Network tab, perform CRUD action, and observe request timing and payload size.

What to look for: Look for long server response times or large JSON payloads indicating inefficient queries.

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