Inserting Documents in a MongoDB Collection

Review the following code, which demonstrates how to insert a single document and multiple documents into a collection.

Insert a Single Document

Use 

insertOne()

 to insert a document into a collection. Within the parentheses of 

insertOne()

, include an object that contains the document data. Here's an example:

db.grades.insertOne({

  student_id: 654321,

  products: [

    {

      type: "exam",

      score: 90,

    },

    {

      type: "homework",

      score: 59,

    },

    {

      type: "quiz",

      score: 75,

    },

    {

      type: "homework",

      score: 88,

    },

  ],

  class_id: 550,

})

Insert Multiple Documents

Use 

insertMany()

 to insert multiple documents at once. Within 

insertMany()

, include the documents within an array. Each document should be separated by a comma. Here's an example:

db.grades.insertMany([

  {

    student_id: 546789,

    products: [

      {

        type: "quiz",

        score: 50,

      },

      {

        type: "homework",

        score: 70,

      },

      {

        type: "quiz",

        score: 66,

      },

      {

        type: "exam",

        score: 70,

      },

    ],

    class_id: 551,

  },

  {

    student_id: 777777,

    products: [

      {

        type: "exam",

        score: 83,

      },

      {

        type: "quiz",

        score: 59,

      },

      {

        type: "quiz",

        score: 72,

      },

      {

        type: "quiz",

        score: 67,

      },

    ],

    class_id: 550,

  },

  {

    student_id: 223344,

    products: [

      {

        type: "exam",

        score: 45,

      },

      {

        type: "homework",

        score: 39,

      },

      {

        type: "quiz",

        score: 40,

      },

      {

        type: "homework",

        score: 88,

      },

    ],

    class_id: 551,

  },

])

Finding Documents in a MongoDB Collection

Review the following code, which demonstrates how to query documents in MongoDB.

Find a Document with Equality

When given equality with an 

_id

 field, the 

find()

 command will return the specified document that matches the 

_id

. Here's an example:

db.zips.find({ _id: ObjectId("5c8eccc1caa187d17ca6ed16") })

Find a Document by Using the 

$in

 Operator

Use the 

$in

 operator to select documents where the value of a field equals any value in the specified array. Here's an example:

db.zips.find({ city: { $in: ["PHOENIX", "CHICAGO"] } })

Finding Documents by Using Comparison Operators

Review the following comparison operators: 

$gt,  $lt, $lte, and  $gte

$gt

Use the 

$gt

 operator to match documents with a field greater than the given value. For example:

db.sales.find({ "items.price": { $gt: 50}})

$lt

Use the 

$lt

 operator to match documents with a field less than the given value. For example:

db.sales.find({ "items.price": { $lt: 50}})

$lte

Use the 

$lte

 operator to match documents with a field less than or equal to the given value. For example:

db.sales.find({ "customer.age": { $lte: 65}})

$gte

Use the 

$gte

 operator to match documents with a field greater than or equal to the given value. For example:

db.sales.find({ "customer.age": { $gte: 65}})

Querying on Array Elements in MongoDB

Review the following code, which demonstrates how to query array elements in MongoDB.

Find Documents with an Array That Contains a Specified Value

In the following example, "InvestmentFund" is not enclosed in square brackets, so MongoDB returns all documents within the 

products

 array that contain the specified value.

db.accounts.find({ products: "InvestmentFund"})

Find a Document by Using the $elemMatch Operator

Use the 

$elemMatch

 operator to find all documents that contain the specified subdocument. For example:

db.sales.find({

  items: {

    $elemMatch: { name: "laptop", price: { $gt: 800 }, quantity: { $gte: 1 } },

  },

})

Querying Subdocuments

Using the transactions collection, search for all accounts with a "sell" transaction which amounts to less than or equal to $4500. Note that the transactions field includes a sub document with an amount for each transaction and a transaction code of either sell or buy.

You are now connected to an Atlas cluster and to the sample_analytics database. Use the transactions collection in this lab.

Lab Instructions

1. Create a query that matches all documents with a transactions sub document that contains an amount less than or equal to $4500 and a transaction_code of "sell" in the transactions collection. 

db.transactions.find({

  transactions: {

    $elemMatch: { amount: { $lte: 4500 }, transaction_code: "sell"}

  },

})

Finding Documents by Using Logical Operators

Review the following logical operators: implicit $and, $or, and $and

Find a Document by Using Implicit  $and

Use implicit 

$and

 to select documents that match multiple expressions. For example:

db.routes.find({ "airline.name": "Southwest Airlines", stops: { $gte: 1 } })

Find a Document by Using the $or Operator

Use the 

$or

 operator to select documents that match at least one of the included expressions. For example:

db.routes.find({

  $or: [{ dst_airport: "SEA" }, { src_airport: "SEA" }],

})

Find a Document by Using the 

$and

 Operator

Use the 

$and

 operator to use multiple 

$or

 expressions in your query.

db.routes.find({

  $and: [

    { $or: [{ dst_airport: "SEA" }, { src_airport: "SEA" }] },

    { $or: [{ "airline.name": "American Airlines" }, { airplane: 320 }] },

  ]

})

Using Logical Operators: And

In this lab, you will find all sales by customers who used a coupon online and are 25 years old or younger.

You are now connected to an Atlas cluster and to the sample_supplies database. Use the sales collection in this lab.

Lab Instructions

1. Find every document in the sales collection that meets the following criteria:

   • Purchased online

   • Used a coupon

   • Purchased by a customer 25 years old or younger

Sample Document

{

  _id: ObjectId("5bd761dcae323e45a93ccfec"),

  saleDate: ISODate("2017-12-03T18:39:48.253Z"),

  items: [

    {

      name: 'backpack',

      tags: [ 'school', 'travel', 'kids' ],

      price: Decimal128("127.59"),

      quantity: 3

    },

    {

      name: 'notepad',

      tags: [ 'office', 'writing', 'school' ],

      price: Decimal128("17.6"),

      quantity: 4

    },

    {

      name: 'binder',

      tags: [ 'school', 'general', 'organization' ],

      price: Decimal128("18.67"),

      quantity: 2

    },

    {

      name: 'pens',

      tags: [ 'writing', 'office', 'school', 'stationary' ],

      price: Decimal128("60.56"),

      quantity: 3

    },

    {

      name: 'notepad',

      tags: [ 'office', 'writing', 'school' ],

      price: Decimal128("28.41"),

      quantity: 1

    },

    {

      name: 'envelopes',

      tags: [ 'stationary', 'office', 'general' ],

      price: Decimal128("15.28"),

      quantity: 7

    },

    {

      name: 'laptop',

      tags: [ 'electronics', 'school', 'office' ],

      price: Decimal128("1259.02"),

      quantity: 3

    }

  ],

  storeLocation: 'London',

  customer: { gender: 'M', age: 40, email: 'dotzu@ib.sh', satisfaction: 4 },

  couponUsed: false,

  purchaseMethod: 'In store'

}

Query:

db.sales.find({ $and: [{ purchaseMethod: "Online" }, { couponUsed: true }, {"customer.age": {$lte:25}} ] }); 

Using Logical Operators: Or

In this lab, you’ll find every sale which contains every item with a writing tag or a name of pens.

You are now connected to an Atlas cluster and to the sample_supplies database. Use the sales collection in this lab.

Lab Instructions

1. Return every document in the sales collection that meets one of the following criteria:

   • Item with the name of pens

   • Item with a writing tag

Sample same as above

db.sales.find({$or: [{"items.name":"pens"}, {"items.tags":"writing"}]});

or 

db.sales.find({ $or: [{ "items.name": "pens" }, { "items.tags": "writing" }], })