Batch delete patterns in Rest API - Mini Project: Build & Apply

Batch Delete Patterns with REST API

📖 Scenario: You are building a simple REST API to manage a list of tasks. Sometimes, users want to delete multiple tasks at once instead of deleting them one by one.Batch deleting helps users save time by removing many tasks in a single request.

🎯 Goal: Build a REST API endpoint that accepts a list of task IDs and deletes all those tasks in one batch operation.You will create the initial data, set up a list of IDs to delete, write the batch delete logic, and finally show the remaining tasks.

📋 What You'll Learn

Create a dictionary called tasks with these exact entries: 1: 'Buy groceries', 2: 'Clean room', 3: 'Pay bills', 4: 'Call mom', 5: 'Read book'

Create a list called delete_ids with these exact values: 2, 4

Use a for loop with variable task_id to iterate over delete_ids and delete each task_id from tasks if it exists

Print the tasks dictionary after deletion to show remaining tasks

💡 Why This Matters

🌍 Real World

Batch deleting is common in apps like email clients, to-do lists, or file managers where users want to remove many items quickly.

💼 Career

Understanding batch operations and safe deletion is important for backend developers building efficient and user-friendly APIs.

1

Create the initial tasks dictionary

Create a dictionary called tasks with these exact entries: 1: 'Buy groceries', 2: 'Clean room', 3: 'Pay bills', 4: 'Call mom', 5: 'Read book'

Rest API

# Create the tasks dictionary with given entries
# Your code here

Hint

Use curly braces {} to create a dictionary with keys as numbers and values as strings.

2

Set up the list of task IDs to delete

Create a list called delete_ids with these exact values: 2, 4

Rest API

tasks = {1: 'Buy groceries', 2: 'Clean room', 3: 'Pay bills', 4: 'Call mom', 5: 'Read book'}
# Create the delete_ids list with values 2 and 4
# Your code here

Hint

Use square brackets [] to create a list with the numbers 2 and 4.

3

Write the batch delete logic

Use a for loop with variable task_id to iterate over delete_ids and delete each task_id from tasks if it exists

Rest API

tasks = {1: 'Buy groceries', 2: 'Clean room', 3: 'Pay bills', 4: 'Call mom', 5: 'Read book'}
delete_ids = [2, 4]
# Use a for loop to delete tasks with IDs in delete_ids
# Your code here

Hint

Use del tasks[task_id] inside the loop to remove the task if it exists.

4

Print the remaining tasks

Write print(tasks) to display the tasks dictionary after deletion

Rest API

tasks = {1: 'Buy groceries', 2: 'Clean room', 3: 'Pay bills', 4: 'Call mom', 5: 'Read book'}
delete_ids = [2, 4]
for task_id in delete_ids:
    if task_id in tasks:
        del tasks[task_id]
# Print the tasks dictionary
# Your code here

Hint

Use print(tasks) to show the dictionary after deletion.

Practice

1.

What is the main advantage of using batch delete in a REST API?

easy

A. It removes multiple items with a single request, saving time.

B. It automatically backs up data before deletion.

C. It encrypts data during deletion.

D. It requires multiple requests for each item.

Solution

1. Step 1: Understand batch delete purpose

   Batch delete is designed to remove many items at once, not one by one.

2. Step 2: Identify the benefit

   Removing multiple items in one request saves time and reduces server load.

3. Final Answer:

   It removes multiple items with a single request, saving time. -> Option A

4. Quick Check:

   Batch delete = single request for many items [OK]

Hint: Batch delete means one request deletes many items [OK]

Common Mistakes:

• Thinking batch delete backs up data
• Confusing batch delete with encryption
• Assuming batch delete needs multiple requests

2.

Which of the following is the correct HTTP method to perform a batch delete in a REST API?

easy

A. GET

B. POST

C. DELETE

D. PUT

Solution

1. Step 1: Recall HTTP methods for REST

   DELETE method is used to remove resources in REST APIs.

2. Step 2: Match method to batch delete

   Batch delete also uses DELETE but with multiple IDs in body or query.

3. Final Answer:

   DELETE -> Option C

4. Quick Check:

   Batch delete uses DELETE method [OK]

Hint: DELETE method removes resources in REST APIs [OK]

Common Mistakes:

• Using POST instead of DELETE for deletion
• Confusing GET with delete operations
• Using PUT which is for updates

3.

Given this REST API call to delete users with IDs 3, 5, and 7:
DELETE /users?ids=3,5,7
What is the expected behavior?

medium

A. Only user with ID 3 is deleted.

B. Users are deleted one by one with separate requests.

C. The server returns an error because multiple IDs are not allowed.

D. Users with IDs 3, 5, and 7 are deleted in one request.

Solution

1. Step 1: Analyze the query parameter usage

   The query parameter 'ids=3,5,7' lists multiple IDs to delete.

2. Step 2: Understand batch delete behavior

   The API deletes all specified users in one DELETE request.

3. Final Answer:

   Users with IDs 3, 5, and 7 are deleted in one request. -> Option D

4. Quick Check:

   Batch delete with multiple IDs = one request deletes all [OK]

Hint: Multiple IDs in query means batch delete in one request [OK]

Common Mistakes:

• Assuming only first ID is deleted
• Thinking server rejects multiple IDs
• Believing multiple requests are sent automatically

4.

Consider this batch delete request:
DELETE /items
with JSON body:
{ "ids": [10, 20, 30] }
But the server responds with 400 Bad Request. What is the likely cause?

medium

A. The JSON format is incorrect.

B. The server expects IDs in the query string, not body.

C. The DELETE method cannot have a request body.

D. The IDs array is empty.

Solution

1. Step 1: Check DELETE method usage

   Some APIs require IDs in query string, not in request body for DELETE.

2. Step 2: Identify server expectation

   Since server returns 400, it likely expects IDs in query parameters, not JSON body.

3. Final Answer:

   The server expects IDs in the query string, not body. -> Option B

4. Quick Check:

   Server expects IDs in query, not body [OK]

Hint: Check if server wants IDs in query or body for DELETE [OK]

Common Mistakes:

• Assuming DELETE cannot have a body always
• Thinking JSON format is wrong without checking
• Ignoring server API documentation

5.

You want to design a batch delete endpoint for a REST API that deletes multiple products by IDs sent in the request body as JSON. Which approach is best practice?

{
  "ids": [101, 102, 103]
}

Choose the correct method and request format.

hard

A. Use DELETE method with JSON body containing IDs array.

B. Use POST method with JSON body containing IDs array.

C. Use DELETE method with IDs in query string separated by commas.

D. Use GET method with IDs in URL path.

Solution

1. Step 1: Understand REST conventions for delete

   DELETE method is standard for removing resources, including batch deletes.

2. Step 2: Check request body usage

   Modern APIs allow DELETE with JSON body to specify multiple IDs for batch delete.

3. Step 3: Evaluate options

   POST is not for deletion, GET is for retrieval, query string can be limited in length.

4. Final Answer:

   Use DELETE method with JSON body containing IDs array. -> Option A

5. Quick Check:

   DELETE + JSON body for batch delete = best practice [OK]

Hint: Use DELETE with JSON body for multiple IDs batch delete [OK]

Common Mistakes:

• Using POST instead of DELETE for deletion
• Putting IDs in query string risking URL length limits
• Using GET which is not for deletion