Stage 2 of 8 · 9 lessons · ~2 weeks

Reading and writing documents

Insert, find, update and delete documents in mongosh: filter with query operators, shape results with projection, sort and limit, change fields with update operators, and know when to upsert or replace.

Start: Inserting documents

Lessons· one lesson for each topic, in this order

Do this

Insert single documents and a batch, and read the returned ids.
Write filters with ranges, $in, $or, $exists and $ne, predicting the count first.
Add projections to every list query you write.
Write a paginated query with sort, skip, limit and a tie-breaker.
Update fields with $set, $inc and $unset and check matchedCount and modifiedCount.
Write an upsert with $setOnInsert.
Run the count-first routine before a deleteMany.

Start with

CourseFree
MongoDB University
MongoDB
Free: the CRUD lessons on inserting, finding, replacing, updating and deleting documents, with labs

Practise

Mongo Playground
Test filters and updates on your own sample documents and share the link when you get stuck

Keep handy

MongoDB Manual
The CRUD operations chapter and the query and update operator reference pages
MongoDB Shell (mongosh)
The mongosh pages on running CRUD commands and reading results

Before moving on: A saved mongosh script of 30 working commands against your sample dataset, each with a comment stating the question it answers or the change it makes, including range filters, a projection, a paginated query, update operators, an upsert and a counted delete.

Tauseef's advice

Before you run a query, guess how many documents it will return, and before you run an update or delete, count what the filter matches. Predicting and then checking catches more bugs than any tool, and it is the habit that stops you wiping a collection on a Friday afternoon.