MongoDB: Deleting Documents

MongoDB: Deleting Documents

Deleting documents in MongoDB removes existing records from a collection. This operation is critical for managing storage, compliance, and application functionality.

Why Delete Documents?

• Data Lifecycle Management: Remove expired or irrelevant data.
• Compliance: Satisfy legal regulations like GDPR or CCPA.
• Storage Optimization: Free up disk space.
• Application Logic: Allow users or systems to delete specific content.

Core Concepts

• Query Filter: Specifies which documents to delete (e.g., { status: "inactive" }). An empty filter {} matches all documents.
• Write Result: Contains metadata like deletedCount, indicating how many documents were removed.

Node.js Examples: Deleting Documents

Sample Data (customers collection):

1. Delete One Document

Delete the document where name is "Company A".

Expected Output:

2. Delete Many Documents

Delete all documents with status equal to "inactive".

Expected Output:

3. Delete All Documents (deleteMany({}))

Output Example:

4. Drop Entire Collection

Use .drop() to delete all documents and the collection structure itself.

Expected Output:

Key Takeaways

• Use deleteOne() to remove a single matching document.
• Use deleteMany() to remove all documents matching a filter or everything with {}.
• Use .drop() to remove the entire collection and its indexes.
• Deletion is irreversible. Always validate filters before execution.