Why document databases over relational in MongoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find all documents in the collection.

MongoDB

db.collection.[1]()

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

Afind

Binsert

Cupdate

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using insert() instead of find() to retrieve data.

Using update() or delete() which modify data, not retrieve.

The find() method retrieves all documents from a MongoDB collection.

2fill in blank

medium

Complete the code to insert a new document into the collection.

MongoDB

db.collection.[1]({ name: 'Alice', age: 30 })

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

Afind

BdeleteOne

CinsertOne

DupdateOne

Attempts:

3 left

💡 Hint

Common Mistakes

Using find() which only retrieves data.

Using deleteOne() or updateOne() which modify or remove data.

The insertOne() method adds a single new document to the collection.

3fill in blank

hard

Fix the error in the query to find documents where age is greater than 25.

MongoDB

db.collection.find({ age: { [1]: 25 } })

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

A$gt

B$lt

C$eq

D$ne

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt which means less than.

Using $eq which means equal to.

Using $ne which means not equal.

The $gt operator means 'greater than' in MongoDB queries.

4fill in blank

hard

Fill both blanks to update the age of a user named 'Bob' to 35.

MongoDB

db.collection.updateOne({ name: 'Bob' }, { [1]: { age: [2] } })

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

A$set

B$inc

C35

D30

Attempts:

3 left

💡 Hint

Common Mistakes

Using $inc which increments a value instead of setting it.

Using the wrong age value.

Omitting the update operator.

The $set operator updates the specified field to a new value, here setting age to 35.

5fill in blank

hard

Fill both blanks to delete all documents where age is less than 20.

MongoDB

db.collection.deleteMany({ age: { [1]: [2] } })

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

A$lt

B20

C$gt

D25

Attempts:

3 left

💡 Hint

Common Mistakes

Using $gt which means greater than.

Using the wrong number for age.

Using deleteOne() which deletes only one document.

The deleteMany() method removes all documents matching the query. The $lt operator means 'less than', so this deletes documents where age is less than 20.