mongodb-crud_skill

Overview

This skill teaches practical MongoDB CRUD operations for developers working with document databases. It covers inserting, querying, updating, and deleting documents, plus BSON types, ObjectId usage, and basic NoSQL patterns. Examples include both JavaScript (Node.js) and Python (PyMongo) so you can apply them in common stacks.

How this skill works

The skill walks through connecting to a MongoDB instance, creating and selecting databases and collections, and performing Create, Read, Update, Delete actions. It explains BSON data types and key concepts like the _id ObjectId, operators ($set, $inc, $push, etc.), and simple aggregation patterns. Code snippets demonstrate single- and bulk-operations, queries by filters and ObjectId, updates (partial and replace), and safe deletion techniques.

When to use it

• Building or maintaining applications that store JSON-like documents
• Migrating relational data to a document model or prototyping NoSQL schemas
• Performing batch updates or cleanup tasks on collections
• Implementing user profiles, logs, or event stores where flexible schema is needed
• Learning core MongoDB concepts before using advanced features like aggregation pipelines

Best practices

• Always handle errors and exceptions around network and DB calls
• Use connection pooling and ensure connections are closed properly
• Validate and sanitize data before insertion to avoid malformed documents
• Index fields that are frequently queried to improve read performance
• Prefer ObjectId for _id and use appropriate write concerns for durability
• Plan for schema evolution and avoid field names that start with $ or contain dots

Example use cases

• Insert single or multiple documents for user accounts, products, or logs
• Query by fields or ObjectId to retrieve specific records or sets of active users
• Update user profiles with $set, increment counters with $inc, and manipulate arrays with $push/$pull
• Replace documents when a full overwrite is required or perform targeted updateMany operations for bulk changes
• Delete stale or soft-deleted records safely, using filters and careful use of deleteMany