How to read records in MongoDB via Node.js?

Q: How to read records in MongoDB via Node.js?

db.collection.find() db.collection.findOne() const cursor = db.collection('inventory').find({}); const cursor = db.collection('inventory').find({ status: 'D' }); const cursor = db.collection('inventory').find({ status: { $in: ['A', 'D'] } }); const cursor = db.collection('inventory').find({ status: 'A', qty: { $lt: 30 } }); const cursor = db.collection('inventory').find({ $or: [{ status: 'A' }, { qty: { $lt: 30 } }] }); const cursor = db.collection('inventory').find({ status: 'A', $or: [{ qty: { $lt: 30 } }, { item: { $regex: '^p' } }] });

Difficulty: 5/10

find queries, cursor pagination, read preferences

MongoDB provides the following methods to read documents from a collection:

1
db.collection.find()
2
db.collection.findOne()

To select all documents in the collection, pass an empty document as the query filter parameter to the find method:

Equality condition:

The following example retrieves all documents from the inventory collection where status equals either 'A' or 'D':

A compound query can specify conditions for more than one field in the collection's documents. Implicitly, a logical AND conjunction connects the clauses of a compound query so that the query selects the documents in the collection that match all the conditions.

Using the $or operator, you can specify a compound query that joins each clause with a logical OR conjunction so that the query selects the documents in the collection that match at least one condition.

AND as well as OR Conditions

Scenario Questions

0-2 years experience

2-5 years experience

1Our API endpoint returns a paginated list of orders. Explain how you would implement pagination using MongoDB cursors in Node.js, and what trade‑offs exist between skip/limit and range‑based pagination.

Follow-up Questions