A brief intro to MongDB.

1. MongoDB
By
Rony Abraham Gregory
Model Engineering College

2. What is MongoDB?
• Humongous (huge + monstrous)
• Document Database
• Schema free
• C++
• Open Source

3. What is MongoDB?
• GNU AGPL v3.0 Licence
• OSX, Linux, Windows, Solaris | 32
bit, 64 bit
• Development and Support by 10gen
and was first released in February 2009
• NoSQL!

4. Database Paradigms
• Relational (RDBMS)
• NoSQL
oKey-value stores
oDocument databases
oWide column stores (BigTable and
clones)
oGraph databases

5. Relational Databases
• ACID (Atomicity Consistency Isolation
and Durability)
• SQL
• MySQL, PostgreSQL, Oracle, etc.

6. Key-value stores
• “One key, one value, no duplicates and
very fast”
• It’s a Hash!
• The value is a binary object aka “blob” –
the DB doesn’t understand it and
doesn’t want to understand it.
• Amazon Dynamo, MemcacheDB, etc.

7. Key-value stores
Fig: A key-value store

8. Document databases
• Key-value stores, but the value is
(usually) structured and “understood”
by the DB.
• Querying data is possible (by means
other than just a key).
• Amazon
SimpleDB, CouchDB, MongoDB, Riak, e
tc.

9. Document databases
Fig: A document database

10. Why NoSQL?
• Schema-free
• Massive data stores
• Scalability
• Some services simpler to implement
than using RDBMS
• Great fit for many Web 2.0 applications

11. Why NOT NoSQL?
• RDBMSes and its tools are mature
• NoSQL implementations are often in
their “alpha” state
• Data consistency, transactions
• “Don’t scale until you need it”

12. RDBMS vs NoSQL
• Strong consistency vs Eventual
consistency
• Big dataset vs HUGE dataset
• Scaling is possible vs Scaling is easy
• Good availability vs Very high
availability

13. RDBMS vs NoSQL
• Strong consistency vs Eventual
consistency
• Big dataset vs HUGE dataset
• Scaling is possible vs Scaling is easy
• Good availability vs Very high
availability

14. RDBMS vs NoSQL
• Strong consistency vs Eventual
consistency
• Big dataset vs HUGE dataset
• Scaling is possible vs Scaling is easy
• Good availability vs Very high
availability

15. Features
• Standard database stuff
• Indexing
• Replication/failover support

16. Features
• Documents are stored in BSON (JSON)
• BSON is a Binary serialization of JSON-
like objects
• This is extremely powerful, because it
means mongoDB understands JSON
natively
• Any valid JSON can be easily imported
and queried

17. Features
• Schema-less; very flexible
• Auto-sharding (alpha)
• Makes for easy horizontal; scaling
• Map/Reduce

18. Features
• Very, very fast
• Super easy to install
• Strong with major languages

19. Features: Querying
• Rich, JavaScript based query syntax
• Allows us to do deep, nested queries
db.order.find( {shipping: { carrier:”usps” }} );
shipping is an embedded document
(object)

20. Features: Official Drivers
• .NET, Java, JavaScript, Ruby, Node.js, PH
P, Haskell, C/C++, Perl

21. Concepts: Document-Oriented
• Think of “documents” as
objects/database records
• Documents are basically just JSON in
binary
• Ability to store information all together

22. Concepts: Document-Oriented

23. Concepts: Document-Oriented
Concept Mapping

24. Concepts: Cursors
• Queries return “cursors” instead of
collections
• A cursor allows you to iterate through
the result set
• A big reason for this is performance
• Much more efficient than loading all
objects into memory

25. Concepts: Cursors
• The find() function returns a cursor
object

26. Basic Operations
• Insert
• Find
• Update
• Remove
• ensureIndex

27. Basic Operations
• Insert
db.test.insert({hello:’world’});
• Find
oEquivalent of Select * FROM test;

28. Basic Operations:Update
db.test.update(<condition>,<operation>)

29. Basic Operations: Remove
db.test.remove(<condition>)

30. Basic Operations: Indexing
• Its usually a good idea to index
collections
• How and which columns depend on
what is to be done
db.test.ensureIndex({hello:I})

31. MongoDB in action!

32. References
• MongoDB home at http://www.mongodb.org
• MongoDB - The Definitive Guide by Kristina
Chodorow and Dirolf
• NoSQL Paper at
http://wiki.hsr.ch/Datenbanken/files/Weber_NoSQL_
Paper.pdf
• Why MongoDB is awesome at
http://www.slideshare.net/jnunemaker/why-
mongodb-is-awesome
• MongoDB wiki at
http://en.wikipedia.org/wiki/MongoDB