Rails Loves MongoDB


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Rails Loves MongoDB. A talk given on 11/21/2013 at the Erie Ruby group. Dives into MongoDB's capabilities and how to use it in a Rails application.

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Rails Loves MongoDB

  1. 1. Rails.loves?(:mongodb) => true A Peek Into Making Awesomely Dynamic Applications
  2. 2. How Many Have Experience With Rails?
  3. 3. How Many Have Experience With Databases?
  4. 4. How Many Have Heard Of MongoDB?
  5. 5. MongoDB Is... Document database (NoSql) (1) Data is stored as BSON Objects (looks exactly like JSON) Gives high performance, high availability, and easy scalability Gives you ultimate flexibility with features like... Sweet Data Types: Hashes and Arrays Allows you to nest documents Allows for dynamic document attributes (1) Despite the word “NoSql” you can still create a relational database with MongoDB
  6. 6. MongoDB In Relational Terms MongoDB MySql Document Row Collection Table Database Database Index Index
  7. 7. More MongoDB Knowledge Two types of relations: Embedded and Referenced No such thing as a “join”, this type of thing can be achieved with embedded documents and linking Has a built in aggregation framework and map reducing support. You still have 1-1, 1-n, n-n relations
  8. 8. What A MongoDB Documents Look Like
  9. 9. How Does Rails Talk To MongoDB? Mongoid - A Object-DocumentMapper(ODM) (1) (1) There are other ODM’s out there for MongoDB, MongoMapper for example. I feel Mongoid is far and away the best one. Has a supportive and active maintainer named Durran Jordan.
  10. 10. Why Not Use ActiveRecord? ActiveRecord does not have built in support for MongoDB. Mongoid replaces it. However, it still uses ActiveModel. You still have all the validation goodness.
  11. 11. Getting Started Install MongoDB...Kind of important Mac: 
 http:/ /docs.mongodb.org/manual/tutorial/install-mongodb-on-windows/ Ubuntu:
 http:/ /docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/
  12. 12. Getting Started With Rails Generate a new Rails 4 Application
  13. 13. Modify Your Gemfile Add the following to your gemfile, then bundle (1)(2) (1) Current public release of Mongoid doesn’t support Rails 4. To install Mongoid 4.0, point the gem to the Mongoid github project. ! (2) If your using Rails 3, use the public gem
  14. 14. Generate A Mongoid Configuration File
  15. 15. What mongoid.yml Looks Like
  16. 16. All Setup. What Kind of App Should We Make? Let’s build an app that helps you track video game achievements that you completed.
  17. 17. What Models Do We Need To Create? system: name, short_name game: title, description, released_at, completed_at achievement: title, description, points, multiplayer, completed_at
  18. 18. Let’s Build A Model Use the Rails generator as normal.
  19. 19. What The Model Looks Like By Default Clean model just includes Mongoid::Document to a class.
  20. 20. Lets Add Some Fields In ActiveRecord you use migrations to add and remove fields from tables. In Mongoid you declare your fields right in the model class.
  21. 21. How About Some Validation
  22. 22. Lets Make Some Relations
  23. 23. The Game Model
  24. 24. The Achievement Model
  25. 25. Lets Review What We Just Did Generated our models Added the fields Added validation Made the relations
  26. 26. Let’s Have Some Fun in Console
  27. 27. Create A System Validation works Document Created
  28. 28. Create A Game For Our System
  29. 29. How About Another Game
  30. 30. Let’s Create An Achievement
  31. 31. How About A Multiplayer Achievement
  32. 32. So How Do These Look Stored In The Database?
  33. 33. How Do The Embedded Documents Look?
  34. 34. We Completed One Of Those Achievements, lets update it
  35. 35. Lets Store A Dynamic Field
  36. 36. Lets Review What We Just Did We created a system called “Xbox One”. We created a new game via our system document, automatically creating the relation to system. We created a new game, then created the relation to system. We can find documents by providing the document ID. Created a single and multiplayer achievement for a game. Took a look and how these are stored in the database. Updated one of the achievements as completed. Updated a document with a dynamic field.
  37. 37. Let’s Try Some Queries
  38. 38. How about all the games that are completed?
  39. 39. How About All Games Who have Achievements With Points Greater than 10?
  40. 40. How About Achievements In A Game With Points Bet ween 10 And 30
  41. 41. Some More Advanced Things You Can Do Custom Validation Methods Callbacks Scoping GeoNear Queries Map Reducing Aggregation Obser vers
  42. 42. Some Resources MongoDB.org - More information about MongoDB RubyonRails.org - Read up on Rails 4 Mongoid.org - Documentation for Mongoid
  43. 43. Follow Me Github - BillWatts Twitter - @BillWatts
  44. 44. Thank You! Get This Project @ http:/ /github.com/ BillWatts/rails_loves_mongodb_talk
  45. 45. Any Questions?