Step 1: Switch to the Database

Before updating data, ensure you're using the correct database.

use myDatabase

Step 2: Check the Existing Data

To see what data exists before updating, use:

db.users.find().pretty()

Step 3: Update a Single Document

To update a single document, use updateOne().

db.users.updateOne(
   { name: "John Doe" }, 
   { $set: { age: 35 } }
)

Step 4: Update Multiple Documents

To update all matching documents, use updateMany().

db.users.updateMany(
   { city: "New York" }, 
   { $set: { status: "Active" } }
)

Step 5: Replace a Document

If you want to completely replace a document, use replaceOne().

db.users.replaceOne(
   { name: "Alice" }, 
   { name: "Alice Brown", age: 28, city: "Chicago" }
)

Step 6: Use Update Operators

MongoDB provides various operators for updates:

1️⃣ Increment a Field ($inc)

db.users.updateOne(
   { name: "John Doe" }, 
   { $inc: { age: 1 } }
)

✅ Increases John's age by 1.

2️⃣ Add a New Field ($set)

db.users.updateOne(
   { name: "Alice" }, 
   { $set: { occupation: "Engineer" } }
)

✅ Adds an occupation field if it doesn't exist.

3️⃣ Remove a Field ($unset)

db.users.updateOne(
   { name: "John Doe" }, 
   { $unset: { age: "" } }
)

Step 7: Verify the Update

After updating, check if the data has changed:

db.users.find({ name: "John Doe" }).pretty()

Conclusion

You’ve learned how to update data in MongoDB using:
✅ updateOne() – Updates the first matching document.
✅ updateMany() – Updates all matching documents.
✅ replaceOne() – Replaces an entire document.
✅ Update operators like $set, $inc, and $unset.

Now, try updating documents in MongoDB with these techniques! 🚀