05‐Replace and Delete Documents

Replacing a Document

To replace documents in MongoDB, we use the replaceOne() method. The replaceOne() method takes the following parameters:

1. filter: A query that matches the document to replace.
2. replacement: The new document to replace the old one with.
3. options: An object that specifies options for the update.

Example

db.books.replaceOne(
  {
    _id: ObjectId("6282afeb441a74a98dbbec4e"),
  },
  {
    title: "Data Science Fundamentals for Python and MongoDB",
    isbn: "1484235967",
    publishedDate: new Date("2018-5-10"),
    thumbnailUrl:
      "https://m.media-amazon.com/images/I/71opmUBc2wL._AC_UY218_.jpg",
    authors: ["David Paper"],
    categories: ["Data Science"],
  }
)

Updating Documents by Using updateOne()

The updateOne() method accepts a filter document, an update document, and an optional options object.

$set

The $set operator replaces the value of a field with the specified value, as shown in the following code:

db.podcasts.updateOne(
  {
    _id: ObjectId("5e8f8f8f8f8f8f8f8f8f8f8"),
  },

  {
    $set: {
      subscribers: 98562,
    },
  }
)

upsert

The upsert option creates a new document if no documents match the filtered criteria. Here's an example:

db.podcasts.updateOne(
  { title: "The Developer Hub" },
  { $set: { topics: ["databases", "MongoDB"] } },
  { upsert: true }
)

$push

The $push operator adds a new value to the hosts array field. Here's an example:

db.podcasts.updateOne(
  { _id: ObjectId("5e8f8f8f8f8f8f8f8f8f8f8") },
  { $push: { hosts: "Nic Raboy" } }
)

Updating Documents by Using findAndModify()

The findAndModify() method is used to find and replace a single document in MongoDB. It accepts a filter document, a replacement document, and an optional options object. The following code shows an example:

db.podcasts.findAndModify({
  query: { _id: ObjectId("6261a92dfee1ff300dc80bf1") },
  update: { $inc: { subscribers: 1 } },
  new: true,
})

Updating Documents by Using updateMany()

To update multiple documents, use the updateMany() method. This method accepts a filter document, an update document, and an optional options object. The following code shows an example:

db.books.updateMany(
  { publishedDate: { $lt: new Date("2019-01-01") } },
  { $set: { status: "LEGACY" } }
)

Deleting Documents in MongoDB

To delete documents, use the deleteOne() or deleteMany() methods. Both methods accept a filter document and an options object.

Delete One Document

The following code shows an example of the deleteOne() method:

db.podcasts.deleteOne({ _id: Objectid("6282c9862acb966e76bbf20a") })

Delete Many Documents

The following code shows an example of the deleteMany() method:

db.podcasts.deleteMany({category: “crime”})