Delete the log entry with `_id: 2` from the `logs` collection. Return all remaining logs.

Problem Statement

<p>Delete the log entry with <code>_id: 2</code> from the <code>logs</code> collection. Return all remaining <code>logs</code>.</p>

Examples

Output: +-----+------------------+-------+ | _id | message | level | +-----+------------------+-------+ | 1 | Server started | info | | 3 | Request received | info | +-----+------------------+-------+

Explanation: The matching documents are removed from the collection and the remaining count is verified.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Use db.<collection>.find(<filter>) to query the documents in the collection. 💡 Hint 2: Pass an empty object {} to retrieve all documents, or specify key-value pairs for exact matching. 💡 Hint 3: Chain .toArray() to resolve the MongoDB cursor into a JavaScript array: return db.<collection>.find(...).toArray();

Editorial & Approach

Problem Overview & Intuition

To solve "Delete One Document (deleteOne)", we query the MongoDB document store. The goal is to delete the log entry with `_id: 2` from the `logs` collection. return all remaining logs. Using a targeted find query, the database engine filters and structures the BSON documents efficiently.

Step-by-Step Approach

Identify Target Collection: Access the collection through the db instance.
Construct Query / Pipeline: Build the query filter with appropriate comparison operators.
Resolve Cursor: Invoke .toArray() to transform the query cursor into the required array of documents.

Optimal Implementation (MongoDB)

function solve(db) {
  db.logs.deleteOne({ _id: 2 });
  return db.logs.find({}).toArray();
}

Complexity Analysis

Time Complexity O(N) collection scan (O(log N) if index is present on filtered fields).

Space Complexity O(K) where K is the number of returned documents in memory.

Key Considerations & Edge Cases

Empty Collections: If no documents match, the query cleanly returns an empty array [].
Missing / NULL Fields: Missing fields in documents are handled safely without throwing runtime exceptions.
Type Coercion: BSON types (ObjectId, Numbers, Strings) are compared strictly according to MongoDB specifications.

Delete One Document (deleteOne)

Easy

Delete the log entry with _id: 2 from the logs collection. Return all remaining logs.

Example Scenarios

1Example 1

Input:

logs collection

_id	message	level
1	Server started	info
2	Deprecated API called	warn
3	Request received	info

Output:

_id	message	level
1	Server started	info
3	Request received	info

Explanation:

The matching documents are removed from the collection and the remaining count is verified.

MongoDB Editor

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Query Results (JSON)

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