Field Update Operators in MongoDB

// Set field values
db.users.updateOne(
  { _id: userId },
  { 
    $set: { name: "John", "address.city": "NYC" },
    $unset: { tempField: "" }
  }
)

// Increment/Decrement
db.products.updateOne(
  { _id: productId },
  { 
    $inc: { 
      views: 1,
      stock: -5 
    }
  }
)

// Multiply value
db.items.updateOne(
  { _id: itemId },
  { $mul: { price: 1.1 } }  // 10% increase
)