Text indexes for search in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a text index on the 'description' field.

MongoDB

db.products.createIndex({ description: [1] })

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

A1

B-1

C"index"

D"text"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 or -1 creates a normal ascending or descending index, not a text index.

Using "index" is not a valid index type.

To create a text index in MongoDB, you specify the field with the value "text".

2fill in blank

medium

Complete the code to search for documents containing the word 'coffee' using the text index.

MongoDB

db.products.find({ $[1]: { $search: "coffee" } })

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

Amatch

Btext

Csearch

Dquery

Attempts:

3 left

💡 Hint

Common Mistakes

Using $match or $search instead of $text causes errors.

Using $query is not valid for text search.

The $text operator is used to perform text search queries in MongoDB.

3fill in blank

hard

Fix the error in the code to create a text index on both 'title' and 'content' fields.

MongoDB

db.articles.createIndex({ title: [1], content: [1] })

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

A-1

B1

C"text"

D"index"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 or -1 for text indexes is incorrect.

Using different types for each field causes errors.

Both fields must be set to "text" to create a compound text index.

4fill in blank

hard

Fill both blanks to perform a text search for 'mongodb' and sort results by text score.

MongoDB

db.blog.find({ $[1]: { $search: "mongodb" } }, { score: { $meta: [2] } }).sort({ score: { $meta: "textScore" } })

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

Atext

BtextScore

Cscore

DsearchScore

Attempts:

3 left

💡 Hint

Common Mistakes

Using $search instead of $text causes errors.

Using incorrect meta values like "score" or "searchScore" fails.

Use $text for the search operator and $meta: "textScore" to get the relevance score.

5fill in blank

hard

Fill all three blanks to create a text index on 'summary', search for 'database', and project the text score.

MongoDB

db.reviews.createIndex({ [1]: [2] });
db.reviews.find({ $[3]: { $search: "database" } }, { score: { $meta: "textScore" } })

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

Asummary

B"text"

Ctext

Dcontent

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong field names or index types.

Using $search instead of $text for the query.

Create the index on 'summary' with type "text", then use $text to search.

Practice

1. What is the main purpose of creating a text index in MongoDB?

easy

A. To encrypt text data for security

B. To enable fast searching of text within string fields

C. To store large text files inside the database

D. To sort documents by text fields alphabetically

Solution

1. Step 1: Understand what a text index does

   A text index allows MongoDB to quickly search text inside string fields of documents.

2. Step 2: Compare options with the purpose

   Sorting, storing files, or encrypting are not functions of text indexes.

3. Final Answer:

   To enable fast searching of text within string fields -> Option B

4. Quick Check:

   Text index = fast text search [OK]

Hint: Text index = fast search inside text fields [OK]

Common Mistakes:

• Confusing text index with sorting index
• Thinking text index stores files
• Assuming text index encrypts data

2. Which of the following is the correct syntax to create a text index on the description field in a MongoDB collection named products?

easy

A. db.products.createTextIndex({ description: 1 })

B. db.products.createIndex({ description: 'string' })

C. db.products.createIndex({ description: 'text' })

D. db.products.createIndex({ description: 1 })

Solution

1. Step 1: Recall the syntax for creating a text index

   The correct method is createIndex with the field set to 'text' type.

2. Step 2: Check each option

   db.products.createIndex({ description: 'text' }) uses createIndex with { description: 'text' }, which is correct. Others use wrong methods or types.

3. Final Answer:

   db.products.createIndex({ description: 'text' }) -> Option C

4. Quick Check:

   Use createIndex with 'text' type [OK]

Hint: Use createIndex({field: 'text'}) to make text index [OK]

Common Mistakes:

• Using 'string' instead of 'text' for index type
• Using createTextIndex (not a valid method)
• Creating normal ascending index (1) instead of text

3. Given a collection articles with a text index on fields title and content, what will the following query return?

db.articles.find({ $text: { $search: "mongodb tutorial" } })

medium

A. Documents containing both words 'mongodb' and 'tutorial' in title or content

B. Documents containing exactly the phrase 'mongodb tutorial' only

C. Documents containing either 'mongodb' or 'tutorial' in any field

D. Documents sorted alphabetically by title

Solution

1. Step 1: Understand $text and $search behavior

   The $search operator looks for documents containing all search words (AND behavior) in indexed text fields.

2. Step 2: Analyze the query

   The query searches for documents with both 'mongodb' and 'tutorial' in either title or content fields.

3. Final Answer:

   Documents containing both words 'mongodb' and 'tutorial' in title or content -> Option A

4. Quick Check:

   $search finds all words, not exact phrase [OK]

Hint: $search finds all words, not exact phrase [OK]

Common Mistakes:

• Thinking $search matches exact phrase only
• Assuming $search matches any single word (OR)
• Expecting sorting by title automatically

4. You tried to create two text indexes on a collection: one on title and another on description. What is the problem with this approach?

medium

A. MongoDB allows only one text index per collection

B. Text indexes must be created on numeric fields only

C. You must create text indexes using createTextIndex method

D. Text indexes cannot be created on multiple fields

Solution

1. Step 1: Recall MongoDB text index limitation

   MongoDB allows only one text index per collection, but it can cover multiple fields.

2. Step 2: Evaluate the options

   MongoDB allows only one text index per collection correctly states the limitation. Others are incorrect about field types or methods.

3. Final Answer:

   MongoDB allows only one text index per collection -> Option A

4. Quick Check:

   One text index per collection rule [OK]

Hint: Only one text index allowed per collection [OK]

Common Mistakes:

• Trying to create multiple text indexes on same collection
• Using wrong method name for creating text index
• Thinking text indexes only work on numbers

5. You want to create a text index on title and summary fields but give title twice the search weight of summary. Which is the correct way to create this weighted text index?

hard

A. db.books.createIndex({ title: 'text', summary: 'text' }, { weights: { summary: 2, title: 1 } })

B. db.books.createIndex({ title: 'text', summary: 'text' }, { weight: { title: 2, summary: 1 } })

C. db.books.createIndex({ title: 'text', summary: 'text' }, { weight: { summary: 2, title: 1 } })

D. db.books.createIndex({ title: 'text', summary: 'text' }, { weights: { title: 2, summary: 1 } })

Solution

1. Step 1: Recall syntax for weighted text indexes

   Weights option is an object named weights specifying field weights.

2. Step 2: Check options for correct spelling and values

   db.books.createIndex({ title: 'text', summary: 'text' }, { weights: { title: 2, summary: 1 } }) uses weights correctly and assigns title weight 2, summary 1 as required.

3. Final Answer:

   db.books.createIndex({ title: 'text', summary: 'text' }, { weights: { title: 2, summary: 1 } }) -> Option D

4. Quick Check:

   Use 'weights' option with correct field weights [OK]

Hint: Use 'weights' option with field weights object [OK]

Common Mistakes:

• Using 'weight' instead of 'weights' option
• Swapping weights between fields
• Not specifying weights object correctly