Array update with $[identifier] filtered in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to update the first matching element in the array.

MongoDB

db.collection.updateOne({ _id: 1 }, { $set: { 'items.$[[1]]': 10 } }, { arrayFilters: [{ '[1].type': 'fruit' }] })

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

Aitem

Belem

Cindex

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names in the update path and arrayFilters.

Using reserved keywords like 'value' as identifier.

The $[identifier] is a placeholder for the array element to update. Here, item is used as the identifier in both the update path and the array filter.

2fill in blank

medium

Complete the code to increment the quantity of all matching array elements.

MongoDB

db.collection.updateMany({}, { $inc: { 'products.$[[1]].quantity': 1 } }, { arrayFilters: [{ '[1].status': 'available' }] })

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

Aindex

Bitem

Celem

Dprod

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching identifier names.

Using invalid identifiers like 'index' which is not an object.

The identifier prod is used to refer to each array element in products that matches the filter status: 'available'.

3fill in blank

hard

Fix the error in the array update by choosing the correct identifier.

MongoDB

db.collection.updateOne({ _id: 5 }, { $set: { 'orders.$[[1]].status': 'shipped' } }, { arrayFilters: [{ '[1].status': 'pending' }] })

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

Aitem

Bord

Corder

Dorders

Attempts:

3 left

💡 Hint

Common Mistakes

Using different identifiers in update path and arrayFilters.

Using plural names for single array elements.

The identifier ord must be used consistently in both the update path and arrayFilters.

4fill in blank

hard

Fill the blanks to update the price of items with quantity less than 5.

MongoDB

db.collection.updateMany({}, { $set: { 'inventory.$[[1]].price': 20 } }, { arrayFilters: [{ '[2].quantity': { $[3]: 5 } }] })

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

Ainv

Blt

Attempts:

3 left

💡 Hint

Common Mistakes

Using different identifiers in update path and arrayFilters.

Using wrong comparison operators like $gt instead of $lt.

The identifier inv is used in both the update path and arrayFilters. The filter checks for quantity less than 5 using $lt.

5fill in blank

hard

Fill all three blanks to increment the score of players with level greater than 10.

MongoDB

db.players.updateMany({}, { $inc: { 'stats.$[[1]].score': [2] } }, { arrayFilters: [{ '[3].level': { $gt: 10 } }] })

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

Astat

B5

Dplayer

Attempts:

3 left

💡 Hint

Common Mistakes

Using different identifiers in update path and arrayFilters.

Using non-numeric values for increment.

The identifier stat is used consistently in the update path and arrayFilters. The score is incremented by 5 for players with level greater than 10.