Embedding vs referencing decision in MongoDB - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to embed an address document inside a user document.

MongoDB

db.users.insertOne({ name: "Alice", address: [1] })

Drag options to blanks, or click blank then click option'

A{ street: "123 Main St", city: "Springfield" }

B"123 Main St"

C["123 Main St", "Springfield"]

DObjectId("507f1f77bcf86cd799439011")

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string or array instead of an embedded document.

Using an ObjectId which is for referencing, not embedding.

Embedding means placing the address document directly inside the user document as a sub-document.

2fill in blank

medium

Complete the code to reference an address document by its ObjectId in the user document.

MongoDB

db.users.insertOne({ name: "Bob", address_id: [1] })

Drag options to blanks, or click blank then click option'

A{ street: "456 Oak St", city: "Greenville" }

BObjectId("507f1f77bcf86cd799439012")

C"456 Oak St"

D["456 Oak St", "Greenville"]

Attempts:

3 left

💡 Hint

Common Mistakes

Embedding the whole address document instead of referencing.

Using a string or array instead of an ObjectId.

Referencing means storing the ObjectId of the related document instead of embedding the whole document.

3fill in blank

hard

Fix the error in the referencing code to correctly store the address reference.

MongoDB

db.users.insertOne({ name: "Carol", address_id: [1] })

Drag options to blanks, or click blank then click option'

A["507f1f77bcf86cd799439013"]

B"507f1f77bcf86cd799439013"

C{ _id: "507f1f77bcf86cd799439013" }

DObjectId("507f1f77bcf86cd799439013")

Attempts:

3 left

💡 Hint

Common Mistakes

Using a plain string instead of ObjectId().

Using an array or object instead of ObjectId.

The address_id field must be an ObjectId type, not a string or array.

4fill in blank

hard

Fill both blanks to embed multiple phone numbers inside a user document.

MongoDB

db.users.insertOne({ name: "Dave", phones: [1] })
// Each phone is a [2]

Drag options to blanks, or click blank then click option'

A[{ type: "home", number: "123-4567" }, { type: "work", number: "987-6543" }]

B"string"

Cobject

D["123-4567", "987-6543"]

Attempts:

3 left

💡 Hint

Common Mistakes

Using an array of strings instead of objects.

Saying each phone is a string instead of an object.

Phones are embedded as an array of objects, each object representing a phone with type and number.

5fill in blank

hard

Fill all three blanks to create a referencing pattern with user and address collections.

MongoDB

const user = {
  name: "Eve",
  address_id: [1]
};

const address = {
  _id: [2],
  street: "789 Pine St",
  city: [3]
};

Drag options to blanks, or click blank then click option'

AObjectId("507f1f77bcf86cd799439014")

B"Springfield"

D"Greenville"

Attempts:

3 left

💡 Hint

Common Mistakes

Using strings instead of ObjectId for IDs.

Mixing up city names or using ObjectId for city.

The user references the address by ObjectId. The address document has the same ObjectId and a city name string.