Combining MongoDB operations

1. Combining MongoDB operations

In the previous chapter, you've learned how to insert, update, and delete documents one function call at a time. But real-world applications often need to run many operations together. That’s why .bulk_write() exists. It lets you combine multiple operations—like inserts, updates, and deletes, all into one request.

2. Building a Bulk Operation

Let’s say we want to insert one movie and update another. Instead of doing two separate calls, we're going to combine them into one bulk_write() operation. We start by importing the necessary operation types: InsertOne and UpdateOne in this case. Then we create a list of operations. Each one behaves exactly like its standalone version: an InsertOne with a document, an UpdateOne with a filter and update object, and so on. Finally, we pass the list to .bulk_write(), which will execute them in order.

3. Understanding the result

After calling .bulk_write(), MongoDB returns a result object that summarizes what happened: how many documents were inserted, modified, or deleted. Just like with standalone inserts or updates, we can read the inserted_count and modified_count. Keep in mind: the operations run in the order you provided. If something fails halfway through, earlier changes are not undone. This means .bulk_write() is fast—but not foolproof. For stricter safety, MongoDB supports the concept of transactions, but those are outside the scope of this course.

4. Why use bulk_write?

So why use .bulk_write()? First, it’s efficient. Instead of multiple round-trips to the database, you send all your operations in a single request. This saves time and reduces network overhead. It’s also easy to track. MongoDB returns a single result object that tells you how many documents were inserted, updated, or deleted. That makes your operations easier to audit and debug. Finally, it keeps your logic clean and readable. Rather than scattering your inserts and updates all over the place, you group them into one clear block of code.

5. What can you combine?

You can mix and match all major operations: inserts, updates, deletes—even replacements. This gives you a flexible toolset to handle complex data syncs, cleanups, or migrations, all in one go.

6. Let's practice!

Now it's time to put your new MongoDB superpower to the test.

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