Batch delete patterns in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Batch delete using query parameters

Consider a REST API endpoint that deletes multiple users by IDs passed as query parameters.

What is the expected HTTP response status code when the following DELETE request is successful?

DELETE /users?ids=1,2,3

A 500 Internal Server Error if any user ID is invalid

B 200 OK with a JSON body listing deleted user IDs

C 404 Not Found if any user ID does not exist

D 204 No Content with an empty response body

💡 Hint

Think about the standard REST practice for successful DELETE requests with no content returned.

204 No Content is the standard response for successful DELETE requests when no response body is returned. Returning 200 OK with a body is possible but less common. 404 or 500 indicate errors.

❓ Predict Output

intermediate

Batch delete with JSON body payload

A REST API supports batch deletion by sending a JSON array of IDs in the request body.

Given this request:

DELETE /items
Content-Type: application/json

[10, 20, 30]

What is the expected output if items 10 and 20 exist but 30 does not?

A {"deleted": [10, 20], "not_found": [30]}

B 204 No Content with empty body

C 404 Not Found with error message for ID 30

D 400 Bad Request due to invalid ID 30

💡 Hint

Consider how partial success is usually reported in batch operations.

When some items are deleted and some are missing, the API commonly returns a JSON object listing which were deleted and which were not found. 204 No Content would not convey partial success. 404 or 400 would reject the entire request.

🧠 Conceptual

advanced

Idempotency in batch delete operations

Why is idempotency important in batch delete REST API endpoints?

A To ensure repeated requests do not cause errors or duplicate deletions

B To allow the server to reject duplicate requests automatically

C To guarantee the server deletes all items regardless of request content

D To require clients to send unique tokens with each request

💡 Hint

Think about what happens if a client sends the same delete request multiple times.

Idempotency means that making the same request multiple times has the same effect as making it once. This prevents errors or unintended side effects from repeated requests.

🔧 Debug

advanced

Debugging batch delete with partial failure

A batch delete API returns this JSON response:

{"deleted": [1, 2], "errors": [{"id": 3, "message": "Permission denied"}]}

What is the most likely cause of this partial failure?

A The request body format is invalid for ID 3

B Item with ID 3 does not exist in the database

C User lacks permission to delete item with ID 3

D The server crashed while deleting item 3

💡 Hint

Look at the error message associated with ID 3.

The error message "Permission denied" indicates the user is not authorized to delete item 3, causing partial failure while other items were deleted successfully.

📝 Syntax

expert

Correct batch delete request format

Which of the following HTTP DELETE requests correctly uses a JSON body to batch delete resources?

A

DELETE /resources
Content-Type: text/plain

ids=5,6,7

B

DELETE /resources
Content-Type: application/json

{"ids": [5, 6, 7]}

C

DELETE /resources
Content-Type: application/json

[5, 6, 7]

D

DELETE /resources/5,6,7
Content-Type: application/json

{}

💡 Hint

Consider the correct use of HTTP method, URL, headers, and body format for batch delete.

Option B correctly sends a DELETE request to the resource endpoint with a JSON body containing an object with an "ids" array. Option B sends a JSON array directly which some APIs may not accept. Option B uses an invalid URL format. Option B uses wrong content type and body format.

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