Custom _id values in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert a document with a custom _id value.

MongoDB

db.collection.insertOne({ _id: [1], name: "Alice" })

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

A"user123"

Bnull

C12345

DObjectId()

Attempts:

3 left

💡 Hint

Common Mistakes

Using ObjectId() when a custom string is needed.

Setting _id to null which is not allowed.

The _id field can be set to a custom string like "user123" to uniquely identify the document.

2fill in blank

medium

Complete the code to find a document by its custom _id value.

MongoDB

db.collection.findOne({ _id: [1] })

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

A"user123"

B123

CObjectId("507f1f77bcf86cd799439011")

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using ObjectId() when the _id is a string.

Using a number when the _id is a string.

To find a document with a custom string _id, use the exact string value in quotes.

3fill in blank

hard

Fix the error in the code to insert a document with a custom numeric _id.

MongoDB

db.collection.insertOne({ _id: [1], name: "Bob" })

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

A"123"

B123

CObjectId()

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string "123" instead of number 123.

Using ObjectId() when a number is needed.

The _id can be a number like 123 without quotes to be numeric.

4fill in blank

hard

Fill both blanks to update a document's name using its custom _id.

MongoDB

db.collection.updateOne({ _id: [1] }, { $set: { name: [2] } })

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

A"user123"

B"Charlie"

C"user456"

D"Dave"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong _id value in the filter.

Not using quotes around the name string.

Use the current _id value to find the document and set the new name as a string.

5fill in blank

hard

Fill all three blanks to insert a document with a custom _id, name, and age.

MongoDB

db.collection.insertOne({ _id: [1], name: [2], age: [3] })

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

A"user789"

B"Eve"

C30

D25

Attempts:

3 left

💡 Hint

Common Mistakes

Putting numbers in quotes.

Using wrong types for _id or name.

Insert a document with a string _id, string name, and numeric age.