bulkWrite() — MongoDB Technical Interview Questions & Answers

Running many insert/update/delete ops in one round-trip.

bulkWrite()

  • Simple meaning: bulkWrite sends many insert/update/delete operations in one round-trip.
  • How to use: db.students.bulkWrite([ { insertOne: { document: { roll: 1 } } }, { updateOne: { filter: { roll: 2 }, update: { $set: { marks: 50 } } } } ]).
  • ordered: true stops on first error.
  • Try this: two operations in one bulkWrite, then find.
  • Common mistake: a loop of insertOne in Node for 10,000 rows — slow. Use insertMany or bulkWrite.
  • Interview tip: Batch writes. Fewer network hops.

Technical Interview Tip: bulkWrite vs a for-loop of insertOne.

Code Examples for bulkWrite()

bulkWrite() — working example

db.users.bulkWrite([
  { insertOne: { document: { name: "Riya", email: "riya@example.com", city: "Pune" } } },
  { updateOne: { filter: { email: "ada@example.com" }, update: { $set: { role: "admin" } } } },
  { deleteOne: { filter: { email: "lin@example.com" } } }
])

bulkWrite() — bulkWrite batches many write operations in one round-trip.

How to Explain bulkWrite() to an Interviewer

Why bulkWrite?

Many writes in one round-trip