Attribute pattern for variable fields in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find documents where the field name starts with 'user_'.

MongoDB

db.collection.find({ [1]: { $exists: true } })

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

A"user_*"

B"user_"

C/^user_/

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes without regex syntax.

Using wildcard characters like '*' inside quotes incorrectly.

The query uses a regular expression to match field names starting with 'user_'. The correct syntax is to use a regex pattern like /^user_/.

2fill in blank

medium

Complete the code to find documents where the field name starts with 'data_'.

MongoDB

db.collection.find({ [1]: { $exists: true } })

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

A"data_.*"

B/^data_/

C"data_*"

D"data_"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wildcard '*' inside quotes without regex.

Using string patterns like 'data_.*' incorrectly.

The query uses a regular expression to match field names starting with 'data_'. The correct syntax is to use a regex pattern like /^data_/.

3fill in blank

hard

Fix the error in the query to find documents with any field starting with 'attr_'.

MongoDB

db.collection.find({ [1]: { $exists: true } })

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

A/^attr_/

B"attr_.*"

C"attr_"

D"attr_*"

Attempts:

3 left

💡 Hint

Common Mistakes

Using string patterns without regex.

Using incorrect regex syntax.

The query needs to use a regular expression to match any field name starting with 'attr_'. Using /^attr_/ as the key in the query is the correct approach.

4fill in blank

hard

Fill both blanks to create a query that finds documents where any field starting with 'meta_' has the value 'active'.

MongoDB

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

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

A/^meta_/

B"active"

Ctrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using string instead of regex for field names.

Using boolean true instead of string 'active'.

The query uses a regex /^meta_/ to match field names starting with 'meta_' and checks if their value is 'active'.

5fill in blank

hard

Fill all three blanks to create an aggregation pipeline that filters documents where the 'info_score' field has a numeric value greater than 10, and projects that field.

MongoDB

db.collection.aggregate([{ $match: { [1]: { $gt: [2] } } }, { $project: { [3]: 1 } }])

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

A"info_score"

B10

D"info_value"

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect field names.

Using string '10' instead of number 10.

The aggregation matches documents where 'info_score' is greater than 10 and projects the 'info_score' field.