10-types-of-arrays.mdx

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👐 Types of arrays

A JSON array can contain simple values (scalar values) or objects. In our data, books have a scalar array of the genres this book belongs to. It also has several arrays of objects, like the authors of a book, attributes, and reviews.

Let's get one book:

Remember to select the books collection in the UI.

[
  { $limit: 1 }
]

db.books.aggregate([
  { $limit: 1 }
])

👐 Run this aggregation to get one book.

I got this one. (It can change depending on the data source you imported.)

[
  {
    "_id": "0002005018",
    "title": "Clara Callan: A novel",
    "authors": [
      {
        "_id": "64cc2db4830ba29148da4c3b",
        "name": "Richard Bruce Wright"
      }
    ],
    "genres": [
      "Women Teachers",
      "Young Women",
      "Actresses",
      "Sisters"
    ],
    "pages": 414,
    "year": 2001,
    "synopsis": "Giller Prize Winner 2001. Richard B. Wright. A Phyllis Bruce Book.",
    "cover": "https://images.isbndb.com/covers/50/12/9780002005012.jpg",
    "attributes": [
      {
        "key": "edition",
        "value": "1st"
      },
      {
        "key": "dimensions",
        "value": "Height: 11.11 Inches, Length: 6.11 Inches, Weight: 1 Pounds, Width: 1.11 Inches"
      },
      {
        "key": "isbn13",
        "value": "9780002005012"
      },
      {
        "key": "msrp",
        "value": "0.00"
      },
      {
        "key": "isbn",
        "value": "0002005018"
      },
      {
        "key": "isbn10",
        "value": "0002005018"
      }
    ],
    "totalInventory": 2,
    "available": 2,
    "binding": "Hardcover",
    "language": "en",
    "publisher": "HarperFlamingoCanada",
    "longTitle": "Clara Callan: A novel",
    "reviews": [
      {
        "_id": {
          "$oid": "6526bbc2e4e804888dfedf37"
        },
        "text": "yd",
        "name": "Holy Dingo",
        "rating": 1,
        "timestamp": 1697037250625
      },
      {
        "_id": {
          "$oid": "651c0f4b24193d51c4c734a3"
        },
        "text": "Great!",
        "name": "Brash Platypus",
        "rating": 5,
        "timestamp": 1696337739128
      }
    ]
  }
]

Array of strings example

  "genres": [
    "Women Teachers",
    "Young Women",
    "Actresses",
    "Sisters"
  ],

Array of objects example

 "attributes": [
    {
      "key": "edition",
      "value": "1st"
    },
    {
      "key": "dimensions",
      "value": "Height: 11.11 Inches, Length: 6.11 Inches, Weight: 1 Pounds, Width: 1.11 Inches"
    },
    {
      "key": "isbn13",
      "value": "9780002005012"
    },
    {
      "key": "msrp",
      "value": "0.00"
    },
    {
      "key": "isbn",
      "value": "0002005018"
    },
    {
      "key": "isbn10",
      "value": "0002005018"
    }
  ],