These exercises and solutions supplement the developerWorks knowledge path "Discover MongoDB."

1. MongoDB supports query joins between collections.
1. True
2. False
2. Replica sets in MongoDB offer the following benefits (pick all that apply):
1. Data redundancy
2. Distributed transaction support
3. Automated failover & high availability
4. Disaster recovery
3. In replica sets, all write requests are automatically sent to secondary nodes directly.
1. True
2. False
4. MongoDB documents are represented as XML.
1. True
2. False
5. Fix this query:

   db.words.find({}).orderBy({spelling:1})

   
   
6. Fix this query:

   db.words.find({}).sort({spelling:1}).rows(3)

   
   
7. Searching for elements in a document array requires you specify a positional element (i.e. document.arrary[i]).
1. True
2. False
8. MongoDB enforces attribute similarity across documents in a collection (i.e. all word documents must have an array of synonyms).
1. True
2. False
9. To find all documents that do not contain the attribute 'synonyms' this query will work.

   db.words.find({synonyms:{$exist:false}})

   
   
1. True
2. False
10. In Mongo, frequently accessed data is stored:
1. On disk
2. In memory
11. MongoDB supports indexes just like any other relational database.
1. True
2. False
12. Indexes can make document queries faster but:
1. They can make inserts and updates slightly slower
2. Require specialized query commands to even be leveraged (in other words, hints)
3. They do not work in a replica set environment

Answers

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Resources

• Discover MongoDB: Follow this knowledge path to master MongoDB's basic and advanced capabilities, and start using it in your programming.
  
  
• developerWorks Java technology zone: Find hundreds of articles about every aspect of Java programming.
  
  

About the author

Andrew Glover is a developer, author, speaker, and entrepreneur with a passion for behavior-driven development, Continuous Integration, and Agile software development. He is the founder of the easyb Behavior-Driven Development (BDD) framework and is the co-author of three books: Continuous Integration, Groovy in Action, and Java Testing Patterns. You can keep up with him at his blog and by following him on Twitter.

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