Atlas search overview in MongoDB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

Find documents matching a text phrase using Atlas Search

Given a collection named books with an Atlas Search index on the title field, what is the output of this query?

MongoDB

db.books.aggregate([
  {
    $search: {
      text: {
        query: "adventure",
        path: "title"
      }
    }
  },
  { $project: { title: 1, _id: 0 } }
])

A [{ "title": "The Great Adventure" }, { "title": "Adventure in the Mountains" }]

B [{ "title": "The Great Adventure" }, { "title": "Cooking Recipes" }]

C [{ "title": "Cooking Recipes" }, { "title": "Gardening Tips" }]

D []

💡 Hint

Think about which titles contain the word 'adventure'.

The $search stage with text operator finds documents where the 'title' field contains the word 'adventure'. Only titles with that word appear in the result.

🧠 Conceptual

intermediate

Understanding Atlas Search index types

Which of the following best describes the purpose of an Atlas Search index in MongoDB?

A It automatically encrypts data at rest in the database.

B It stores backup copies of the database for disaster recovery.

C It enables fast, full-text search queries on specified fields using Lucene technology.

D It manages user authentication and access control.

💡 Hint

Atlas Search uses a popular open-source search engine technology.

Atlas Search indexes use Apache Lucene to provide fast and rich full-text search capabilities on MongoDB collections.

📝 Syntax

advanced

Identify the syntax error in this Atlas Search query

What error does this query raise?

MongoDB

db.products.aggregate([
  {
    $search: {
      text: {
        query: "smartphone",
        path: ["name", "description"]
      }
    }
  }
])

A SyntaxError: The 'path' field must be a string, not an array.

B RuntimeError: The $search stage is not supported in aggregate pipelines.

C TypeError: The 'query' field must be an array of strings.

D No error; the query runs successfully and returns matching documents.

💡 Hint

Check the Atlas Search documentation for the 'text' operator's 'path' field type.

The 'path' field in the text operator can accept either a string or an array of strings to search multiple fields.

❓ optimization

advanced

Improve performance of an Atlas Search query filtering by category

You want to find documents with 'laptop' in the 'title' and category 'electronics'. Which query is more efficient?

A Use $search with compound operator combining text on 'title' and equals on 'category'.

B Use $match on 'category' first, then $search with text operator on 'title'.

C Use $search with text operator on 'title' and then $match on 'category' after $search.

D Use $match on both 'title' and 'category' without $search.

💡 Hint

Atlas Search compound operator can combine multiple conditions efficiently.

Using the compound operator inside $search allows filtering and text search in one stage, improving performance.

🔧 Debug

expert

Why does this Atlas Search query return no results?

Given this query, why might it return an empty result set?

MongoDB

db.orders.aggregate([
  {
    $search: {
      text: {
        query: "urgent",
        path: "status"
      }
    }
  }
])

A The query syntax is invalid because 'query' must be an array, not a string.

B The 'status' field is not included in the Atlas Search index, so no matches are found.

C The $search stage cannot be used on fields with string values.

D The collection 'orders' does not exist, causing the query to return no results.

💡 Hint

Check if the field you search is indexed by Atlas Search.

Atlas Search only searches fields included in its index. If 'status' is not indexed, no documents match.