Chapter 15: MongoDB Aggregation $project
1. What does $project really do? (Teacher explanation — no jargon first) $project lets you: Decide which fields you want to keep in the output documents Decide which fields you want to remove Rename...
Category: MongoDB
Chapter 14: MongoDB Aggregation $limit
1. What does $limit actually do? (Plain teacher language) $limit tells the aggregation pipeline: “After the previous stages have done their work, only pass the first N documents to the next stage (or to...
Chapter 13: MongoDB Aggregation $group
1. What does $group actually do? (Simple teacher explanation) $group collects documents that have the same value(s) in one or more fields (the grouping key), and then lets you calculate something about each group....
Chapter 12: MongoDB Aggregation Pipelines
MongoDB Aggregation Pipelines. ❤️📊📈 This is not just another query. This is where MongoDB becomes a full-fledged data transformation & analytics engine inside the database — no need to pull millions of documents to...
Chapter 11: MongoDB Update Operators
MongoDB Update Operators — the $ prefixed tools you put in the second argument of updateOne(), updateMany(), findOneAndUpdate(), replaceOne() (sometimes), and even aggregation $merge/$set stages. These operators are what make updates atomic, efficient, and...
Chapter 10: MongoDB Query Operators
1. What Exactly Are MongoDB Query Operators? (Big Picture) Query operators are prefixed with $ keywords that tell MongoDB how to compare, match, combine, or evaluate field values. Official categories (as per MongoDB 8.0...
Chapter 9: MongoDB mongosh Delete
MongoDB mongosh Delete — the D in CRUD. This is how you permanently remove documents from a collection. Once deleted, they’re gone (unless you have backups or oplog/time-travel — but that’s advanced). 1. The...
Chapter 8: MongoDB mongosh Update
MongoDB mongosh Update — the U in CRUD. This is how you modify existing documents without deleting and re-inserting everything. 1. The Two Main Update Methods in mongosh (2026 Standard) Method What it does...
Chapter 7: MongoDB mongosh Find
MongoDB mongosh Find (aka the most used command after insert — Read / Retrieve data using find() and friends) This is the R in CRUD — the heart of almost every app. find() is...
Chapter 6: MongoDB mongosh Insert
MongoDB mongosh Insert (aka How to add data using insertOne() and insertMany() in the mongosh shell) This is the C in CRUD — Create / Insert operations. It’s how you bring new documents (your...
