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👐 INSERT → insertOne() & DELETE → deleteOne()

MongoDB provides two methods for inserting documents into a collection:

  • .insertOne(): Inserts a single document
  • .insertMany(): Inserts multiple documents at once

And just like insert, MongoDB provides:

  • .deleteOne(): Deletes the first matching document.
  • .deleteMany(): Deletes all matching documents.

Example: Insert a new review​

db.reviews.insertOne({
  text: "Best book I have ever read.",
  rating: 5,
  name: "Jack",
  bookId: "0786222727",
});

Equivalent SQL query​

INSERT INTO reviews (text, rating, name, bookId)
VALUES ('Best book I have ever read.', 5, 'Jack', '0786222727');

Example: Insert multiple reviews​

db.reviews.insertMany([
  {
    text: "Amazing plot.",
    rating: 5,
    name: "John",
    bookId: "0786222727",
  },
  {
    text: "Over-hyped, tbh I feel it's very boring!",
    rating: 2,
    name: "Nick",
    bookId: "0786222727",
  },
]);

Example: Delete one review​

db.reviews.deleteOne({
  bookId: "0786222727",
});

Equivalent SQL query​

DELETE FROM reviews WHERE bookId = '0786222727';

Challenge​

👐 1. Insert 4 more reviews for bookId "0786222727".​

Answer
  db.reviews.insertMany([
    {
      text: "Thrilling end.",
      rating: 4,
      name: "Mark",
      bookId: "0786222727",
    },
    {
      text: "Must read!",
      rating: 5,
      name: "Raj",
      bookId: "0786222727",
    },
    {
      text: "Very expensive",
      rating: 3,
      name: "Yun",
      bookId: "0786222727",
    },
    {
      text: "Extremely satisfied with the storyline!",
      rating: 5,
      name: "Lisa",
      bookId: "0786222727",
    }
  ]);

👐 2. Delete all the reviews for bookId "0786222727" through a single command.​

Answer
  db.reviews.deleteMany({"bookId": "0786222727"})